feat: side panels for properties and tools

src/App.tsx

@@ -1,7 +1,8 @@
 import { useState, useCallback, useEffect } from "react";
 import { ReactFlowProvider, useReactFlow } from "reactflow";
 import GraphEditor from "./components/Editor/GraphEditor";
-import Toolbar from "./components/Toolbar/Toolbar";
+import LeftPanel from "./components/Panels/LeftPanel";
+import RightPanel from "./components/Panels/RightPanel";
 import DocumentTabs from "./components/Workspace/DocumentTabs";
 import MenuBar from "./components/Menu/MenuBar";
 import DocumentManager from "./components/Workspace/DocumentManager";
@@ -10,6 +11,8 @@ import { KeyboardShortcutProvider } from "./contexts/KeyboardShortcutContext";
 import { useGlobalShortcuts } from "./hooks/useGlobalShortcuts";
 import { useDocumentHistory } from "./hooks/useDocumentHistory";
 import { useWorkspaceStore } from "./stores/workspaceStore";
+import { usePanelStore } from "./stores/panelStore";
+import type { Actor, Relation } from "./types";
 
 /**
  * App - Root application component
@@ -34,10 +37,14 @@ import { useWorkspaceStore } from "./stores/workspaceStore";
 function AppContent() {
   const { undo, redo } = useDocumentHistory();
   const { activeDocumentId } = useWorkspaceStore();
+  const { toggleLeftPanel, toggleRightPanel, leftPanelVisible, rightPanelVisible } = usePanelStore();
   const [showDocumentManager, setShowDocumentManager] = useState(false);
   const [showKeyboardHelp, setShowKeyboardHelp] = useState(false);
+  const [selectedNode, setSelectedNode] = useState<Actor | null>(null);
+  const [selectedEdge, setSelectedEdge] = useState<Relation | null>(null);
   const { fitView } = useReactFlow();
 
+
   // Listen for document manager open event from EmptyState
   useEffect(() => {
     const handleOpenDocumentManager = () => {
@@ -71,6 +78,33 @@ function AppContent() {
     onSelectAll: handleSelectAll,
   });
 
+  // Panel toggle keyboard shortcuts
+  useEffect(() => {
+    const handleKeyDown = (e: KeyboardEvent) => {
+      // Ctrl+B: Toggle left panel
+      if (e.ctrlKey && e.key === 'b') {
+        e.preventDefault();
+        toggleLeftPanel();
+      }
+      // Ctrl+I: Toggle right panel
+      if (e.ctrlKey && e.key === 'i') {
+        e.preventDefault();
+        toggleRightPanel();
+      }
+      // Escape: Close property panels
+      if (e.key === 'Escape') {
+        if (selectedNode || selectedEdge) {
+          e.preventDefault();
+          setSelectedNode(null);
+          setSelectedEdge(null);
+        }
+      }
+    };
+
+    window.addEventListener('keydown', handleKeyDown);
+    return () => window.removeEventListener('keydown', handleKeyDown);
+  }, [toggleLeftPanel, toggleRightPanel, selectedNode, selectedEdge]);
+
   return (
     <div className="flex flex-col h-screen bg-gray-100">
       {/* Header */}
@@ -102,12 +136,51 @@ function AppContent() {
       {/* Document Tabs */}
       <DocumentTabs />
 
-      {/* Toolbar - only show when a document is active */}
-      {activeDocumentId && <Toolbar />}
+      {/* Main content area with side panels */}
+      <main className="flex-1 overflow-hidden flex">
+        {/* Left Panel */}
+        {leftPanelVisible && activeDocumentId && (
+          <LeftPanel
+            onDeselectAll={() => {
+              setSelectedNode(null);
+              setSelectedEdge(null);
+            }}
+          />
+        )}
 
-      {/* Main graph editor */}
-      <main className="flex-1 overflow-hidden">
-        <GraphEditor />
+        {/* Center: Graph Editor */}
+        <div className="flex-1 overflow-hidden">
+          <GraphEditor
+            selectedNode={selectedNode}
+            selectedEdge={selectedEdge}
+            onNodeSelect={(node) => {
+              setSelectedNode(node);
+              // Only clear edge if we're setting a node (not clearing)
+              if (node) {
+                setSelectedEdge(null);
+              }
+            }}
+            onEdgeSelect={(edge) => {
+              setSelectedEdge(edge);
+              // Only clear node if we're setting an edge (not clearing)
+              if (edge) {
+                setSelectedNode(null);
+              }
+            }}
+          />
+        </div>
+
+        {/* Right Panel */}
+        {rightPanelVisible && activeDocumentId && (
+          <RightPanel
+            selectedNode={selectedNode}
+            selectedEdge={selectedEdge}
+            onClose={() => {
+              setSelectedNode(null);
+              setSelectedEdge(null);
+            }}
+          />
+        )}
       </main>
 
       {/* Document Manager Modal */}

src/components/Editor/GraphEditor.tsx

@@ -17,6 +17,7 @@ import ReactFlow, {
   ConnectionMode,
   useReactFlow,
   Viewport,
+  useOnSelectionChange,
 } from 'reactflow';
 import 'reactflow/dist/style.css';
 
@@ -27,8 +28,6 @@ import { useActiveDocument } from '../../stores/workspace/useActiveDocument';
 import { useWorkspaceStore } from '../../stores/workspaceStore';
 import CustomNode from '../Nodes/CustomNode';
 import CustomEdge from '../Edges/CustomEdge';
-import EdgePropertiesPanel from './EdgePropertiesPanel';
-import NodePropertiesPanel from './NodePropertiesPanel';
 import ContextMenu from './ContextMenu';
 import EmptyState from '../Common/EmptyState';
 import { createNode } from '../../utils/nodeUtils';
@@ -38,6 +37,13 @@ import { useConfirm } from '../../hooks/useConfirm';
 
 import type { Actor, Relation } from '../../types';
 
+interface GraphEditorProps {
+  selectedNode: Actor | null;
+  selectedEdge: Relation | null;
+  onNodeSelect: (node: Actor | null) => void;
+  onEdgeSelect: (edge: Relation | null) => void;
+}
+
 /**
  * GraphEditor - Main interactive graph visualization component
  *
@@ -51,7 +57,7 @@ import type { Actor, Relation } from '../../types';
  *
  * Usage: Core component that wraps React Flow with custom nodes and edges
  */
-const GraphEditor = () => {
+const GraphEditor = ({ onNodeSelect, onEdgeSelect }: GraphEditorProps) => {
   // Sync with workspace active document
   const { activeDocumentId } = useActiveDocument();
   const { saveViewport, getViewport, createDocument } = useWorkspaceStore();
@@ -90,10 +96,6 @@ const GraphEditor = () => {
   // Track if a drag is in progress to capture state before drag
   const dragInProgressRef = useRef(false);
 
-  // Selected edge/node state for properties panels
-  const [selectedEdge, setSelectedEdge] = useState<Relation | null>(null);
-  const [selectedNode, setSelectedNode] = useState<Actor | null>(null);
-
   // Context menu state
   const [contextMenu, setContextMenu] = useState<{
     x: number;
@@ -148,6 +150,35 @@ const GraphEditor = () => {
     [activeDocumentId, saveViewport]
   );
 
+  // Handle selection changes using ReactFlow's dedicated hook
+  const handleSelectionChange = useCallback(
+    ({ nodes: selectedNodes, edges: selectedEdges }: { nodes: Node[]; edges: Edge[] }) => {
+      // If a node is selected, notify parent
+      if (selectedNodes.length > 0) {
+        const selectedNode = selectedNodes[0] as Actor;
+        onNodeSelect(selectedNode);
+        // Don't call onEdgeSelect - parent will handle clearing edge selection
+      }
+      // If an edge is selected, notify parent
+      else if (selectedEdges.length > 0) {
+        const selectedEdge = selectedEdges[0] as Relation;
+        onEdgeSelect(selectedEdge);
+        // Don't call onNodeSelect - parent will handle clearing node selection
+      }
+      // Nothing selected
+      else {
+        onNodeSelect(null);
+        onEdgeSelect(null);
+      }
+    },
+    [onNodeSelect, onEdgeSelect]
+  );
+
+  // Register the selection change handler with ReactFlow
+  useOnSelectionChange({
+    onChange: handleSelectionChange,
+  });
+
   // Sync React Flow state back to store when nodes/edges change
   // IMPORTANT: This handler tracks drag operations for undo/redo
   const handleNodesChange = useCallback(
@@ -184,8 +215,11 @@ const GraphEditor = () => {
         dragInProgressRef.current = false;
         // Debounce to allow React Flow state to settle
         setTimeout(() => {
-          // Sync to store
-          setNodes(nodes as Actor[]);
+          // Sync to store - use callback to get fresh state
+          setNodesState((currentNodes) => {
+            setNodes(currentNodes as Actor[]);
+            return currentNodes;
+          });
         }, 0);
       } else {
         // For non-drag changes (dimension, etc), just sync to store
@@ -194,17 +228,21 @@ const GraphEditor = () => {
         );
         if (hasNonSelectionChanges) {
           setTimeout(() => {
-            setNodes(nodes as Actor[]);
+            setNodesState((currentNodes) => {
+              setNodes(currentNodes as Actor[]);
+              return currentNodes;
+            });
           }, 0);
         }
       }
     },
-    [onNodesChange, nodes, setNodes, pushToHistory]
+    [onNodesChange, setNodesState, setNodes, pushToHistory]
   );
 
   const handleEdgesChange = useCallback(
     (changes: EdgeChange[]) => {
       onEdgesChange(changes);
+
       // Only sync to store for non-selection changes
       const hasNonSelectionChanges = changes.some(
         (change) => change.type !== 'select' && change.type !== 'remove'
@@ -212,11 +250,14 @@ const GraphEditor = () => {
       if (hasNonSelectionChanges) {
         // Debounce store updates to avoid loops
         setTimeout(() => {
-          setEdges(edges as Relation[]);
+          setEdgesState((currentEdges) => {
+            setEdges(currentEdges as Relation[]);
+            return currentEdges;
+          });
         }, 0);
       }
     },
-    [onEdgesChange, edges, setEdges]
+    [onEdgesChange, setEdgesState, setEdges]
   );
 
   // Handle new edge connections
@@ -235,18 +276,23 @@ const GraphEditor = () => {
           type: edgeType,
           // Don't set label - will use type's label as default
         },
+        selected: true, // Auto-select the new edge in ReactFlow
       };
 
       // Use React Flow's addEdge helper to properly format the edge
       const updatedEdges = addEdge(edgeWithData, storeEdges as Edge[]);
 
+      // Deselect all nodes
+      const updatedNodes = nodes.map((node) => ({ ...node, selected: false }));
+      setNodesState(updatedNodes as Node[]);
+
       // Find the newly added edge (it will be the last one)
       const newEdge = updatedEdges[updatedEdges.length - 1] as Relation;
 
       // Use the history-tracked addEdge function
       addEdgeWithHistory(newEdge);
     },
-    [storeEdges, edgeTypeConfigs, addEdgeWithHistory, selectedRelationType]
+    [storeEdges, edgeTypeConfigs, addEdgeWithHistory, selectedRelationType, nodes, setNodesState]
   );
 
   // Handle node deletion
@@ -285,40 +331,22 @@ const GraphEditor = () => {
     []
   );
 
-  // Handle edge double-click to show properties
-  const handleEdgeDoubleClick = useCallback(
-    (_event: React.MouseEvent, edge: Edge) => {
-      setSelectedNode(null); // Close node panel if open
-      setSelectedEdge(edge as Relation);
+  // Handle node click - ReactFlow handles selection automatically
+  const handleNodeClick = useCallback(
+    (_event: React.MouseEvent, _node: Node) => {
       setContextMenu(null); // Close context menu if open
     },
     []
   );
 
-  // Handle node double-click to show properties
-  const handleNodeDoubleClick = useCallback(
-    (_event: React.MouseEvent, node: Node) => {
-      setSelectedEdge(null); // Close edge panel if open
-      setSelectedNode(node as Actor);
+  // Handle edge click - ReactFlow handles selection automatically
+  const handleEdgeClick = useCallback(
+    (_event: React.MouseEvent, _edge: Edge) => {
       setContextMenu(null); // Close context menu if open
     },
     []
   );
 
-  // Handle node click to close context menu
-  const handleNodeClick = useCallback(() => {
-    if (contextMenu) {
-      setContextMenu(null);
-    }
-  }, [contextMenu]);
-
-  // Handle edge click to close context menu
-  const handleEdgeClick = useCallback(() => {
-    if (contextMenu) {
-      setContextMenu(null);
-    }
-  }, [contextMenu]);
-
   // Handle right-click on pane (empty space)
   const handlePaneContextMenu = useCallback(
     (event: React.MouseEvent) => {
@@ -379,12 +407,19 @@ const GraphEditor = () => {
 
       const nodeTypeConfig = nodeTypeConfigs.find((nt) => nt.id === nodeTypeId);
       const newNode = createNode(nodeTypeId, position, nodeTypeConfig);
+      newNode.selected = true; // Auto-select the new node in ReactFlow
+
+      // Deselect all existing nodes and edges BEFORE adding the new one
+      const updatedNodes = nodes.map((node) => ({ ...node, selected: false }));
+      const updatedEdges = edges.map((edge) => ({ ...edge, selected: false }));
+      setNodesState(updatedNodes as Node[]);
+      setEdgesState(updatedEdges as Edge[]);
 
       // Use history-tracked addNode instead of setNodes
       addNodeWithHistory(newNode);
       setContextMenu(null);
     },
-    [contextMenu, screenToFlowPosition, nodeTypeConfigs, addNodeWithHistory]
+    [contextMenu, screenToFlowPosition, nodeTypeConfigs, addNodeWithHistory, nodes, edges, setNodesState, setEdgesState]
   );
 
   // Show empty state when no document is active
@@ -413,8 +448,6 @@ const GraphEditor = () => {
         onEdgesDelete={handleEdgesDelete}
         onNodeClick={handleNodeClick}
         onEdgeClick={handleEdgeClick}
-        onEdgeDoubleClick={handleEdgeDoubleClick}
-        onNodeDoubleClick={handleNodeDoubleClick}
         onNodeContextMenu={handleNodeContextMenu}
         onEdgeContextMenu={handleEdgeContextMenu}
         onPaneContextMenu={handlePaneContextMenu}
@@ -459,16 +492,6 @@ const GraphEditor = () => {
         />
       </ReactFlow>
 
-      {/* Property Panels */}
-      <EdgePropertiesPanel
-        selectedEdge={selectedEdge}
-        onClose={() => setSelectedEdge(null)}
-      />
-      <NodePropertiesPanel
-        selectedNode={selectedNode}
-        onClose={() => setSelectedNode(null)}
-      />
-
       {/* Context Menu - Pane */}
       {contextMenu && contextMenu.type === 'pane' && (
         <ContextMenu
@@ -500,7 +523,15 @@ const GraphEditor = () => {
                   label: 'Edit Properties',
                   icon: <EditIcon fontSize="small" />,
                   onClick: () => {
-                    setSelectedNode(contextMenu.target as Actor);
+                    // Select the node in ReactFlow (which will trigger the right panel)
+                    const nodeId = contextMenu.target!.id;
+                    const updatedNodes = nodes.map((n) => ({
+                      ...n,
+                      selected: n.id === nodeId,
+                    }));
+                    const updatedEdges = edges.map((e) => ({ ...e, selected: false }));
+                    setNodesState(updatedNodes as Node[]);
+                    setEdgesState(updatedEdges as Edge[]);
                     setContextMenu(null);
                   },
                 },
@@ -539,7 +570,15 @@ const GraphEditor = () => {
                   label: 'Edit Properties',
                   icon: <EditIcon fontSize="small" />,
                   onClick: () => {
-                    setSelectedEdge(contextMenu.target as Relation);
+                    // Select the edge in ReactFlow (which will trigger the right panel)
+                    const edgeId = contextMenu.target!.id;
+                    const updatedEdges = edges.map((e) => ({
+                      ...e,
+                      selected: e.id === edgeId,
+                    }));
+                    const updatedNodes = nodes.map((n) => ({ ...n, selected: false }));
+                    setEdgesState(updatedEdges as Edge[]);
+                    setNodesState(updatedNodes as Node[]);
                     setContextMenu(null);
                   },
                 },

src/components/Panels/LeftPanel.tsx

@@ -0,0 +1,288 @@
+import { useCallback } from 'react';
+import { IconButton, Tooltip } from '@mui/material';
+import ChevronLeftIcon from '@mui/icons-material/ChevronLeft';
+import ChevronRightIcon from '@mui/icons-material/ChevronRight';
+import UndoIcon from '@mui/icons-material/Undo';
+import RedoIcon from '@mui/icons-material/Redo';
+import ExpandMoreIcon from '@mui/icons-material/ExpandMore';
+import ExpandLessIcon from '@mui/icons-material/ExpandLess';
+import { usePanelStore } from '../../stores/panelStore';
+import { useGraphWithHistory } from '../../hooks/useGraphWithHistory';
+import { useEditorStore } from '../../stores/editorStore';
+import { useDocumentHistory } from '../../hooks/useDocumentHistory';
+import { createNode } from '../../utils/nodeUtils';
+
+/**
+ * LeftPanel - Collapsible tools panel on the left side
+ *
+ * Features:
+ * - Collapsible sections (History, Add Actors, Relations, Layout, View, Search)
+ * - Drag-and-drop actor creation
+ * - Undo/Redo with descriptions
+ * - Relation type selector
+ * - Collapse to icon bar (40px)
+ * - Resizable width
+ */
+
+interface LeftPanelProps {
+  onDeselectAll: () => void;
+}
+
+const LeftPanel = ({ onDeselectAll }: LeftPanelProps) => {
+  const {
+    leftPanelCollapsed,
+    leftPanelWidth,
+    leftPanelSections,
+    toggleLeftPanelSection,
+    collapseLeftPanel,
+    expandLeftPanel,
+  } = usePanelStore();
+
+  const { nodeTypes, edgeTypes, addNode } = useGraphWithHistory();
+  const { selectedRelationType, setSelectedRelationType } = useEditorStore();
+  const { undo, redo, canUndo, canRedo, undoDescription, redoDescription } = useDocumentHistory();
+
+  const handleAddNode = useCallback(
+    (nodeTypeId: string) => {
+      // Deselect all other nodes/edges first
+      onDeselectAll();
+
+      // Create node at center of viewport (approximate)
+      const position = {
+        x: Math.random() * 400 + 100,
+        y: Math.random() * 300 + 100,
+      };
+
+      const nodeTypeConfig = nodeTypes.find((nt) => nt.id === nodeTypeId);
+      const newNode = createNode(nodeTypeId, position, nodeTypeConfig);
+      newNode.selected = true; // Auto-select in ReactFlow
+
+      addNode(newNode);
+    },
+    [addNode, nodeTypes, onDeselectAll]
+  );
+
+  const selectedEdgeTypeConfig = edgeTypes.find(et => et.id === selectedRelationType);
+
+  // Collapsed icon bar view
+  if (leftPanelCollapsed) {
+    return (
+      <div className="h-full bg-gray-50 border-r border-gray-200 flex flex-col items-center py-2 space-y-2" style={{ width: '40px' }}>
+        <Tooltip title="Expand Tools Panel (Ctrl+B)" placement="right">
+          <IconButton size="small" onClick={expandLeftPanel}>
+            <ChevronRightIcon fontSize="small" />
+          </IconButton>
+        </Tooltip>
+
+        {/* Icon indicators for quick reference */}
+        <div className="flex-1 flex flex-col items-center space-y-4 pt-4">
+          <Tooltip title={`Undo: ${undoDescription || 'Nothing to undo'}`} placement="right">
+            <span>
+              <IconButton size="small" onClick={undo} disabled={!canUndo}>
+                <UndoIcon fontSize="small" />
+              </IconButton>
+            </span>
+          </Tooltip>
+        </div>
+      </div>
+    );
+  }
+
+  // Expanded panel view
+  return (
+    <div
+      className="h-full bg-white border-r border-gray-200 flex flex-col overflow-hidden"
+      style={{ width: `${leftPanelWidth}px` }}
+    >
+      {/* Header */}
+      <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
+        <h2 className="text-sm font-semibold text-gray-700">Tools</h2>
+        <Tooltip title="Collapse Panel (Ctrl+B)">
+          <IconButton size="small" onClick={collapseLeftPanel}>
+            <ChevronLeftIcon fontSize="small" />
+          </IconButton>
+        </Tooltip>
+      </div>
+
+      {/* Scrollable content */}
+      <div className="flex-1 overflow-y-auto overflow-x-hidden">
+        {/* History Section */}
+        <div className="border-b border-gray-200">
+          <button
+            onClick={() => toggleLeftPanelSection('history')}
+            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
+          >
+            <span className="text-xs font-semibold text-gray-700">History</span>
+            {leftPanelSections.history ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
+          </button>
+          {leftPanelSections.history && (
+            <div className="px-3 py-3 space-y-2">
+              <div className="flex items-center space-x-1">
+                <Tooltip
+                  title={undoDescription ? `Undo: ${undoDescription}` : 'Undo (Ctrl+Z)'}
+                  arrow
+                >
+                  <span className="flex-1">
+                    <button
+                      onClick={undo}
+                      disabled={!canUndo}
+                      className="w-full flex items-center space-x-2 px-2 py-1.5 text-xs font-medium text-gray-700 bg-gray-50 rounded hover:bg-gray-100 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
+                    >
+                      <UndoIcon fontSize="small" />
+                      <span>Undo</span>
+                    </button>
+                  </span>
+                </Tooltip>
+                <Tooltip
+                  title={redoDescription ? `Redo: ${redoDescription}` : 'Redo (Ctrl+Y)'}
+                  arrow
+                >
+                  <span className="flex-1">
+                    <button
+                      onClick={redo}
+                      disabled={!canRedo}
+                      className="w-full flex items-center space-x-2 px-2 py-1.5 text-xs font-medium text-gray-700 bg-gray-50 rounded hover:bg-gray-100 disabled:opacity-40 disabled:cursor-not-allowed transition-colors"
+                    >
+                      <RedoIcon fontSize="small" />
+                      <span>Redo</span>
+                    </button>
+                  </span>
+                </Tooltip>
+              </div>
+              {undoDescription && (
+                <p className="text-xs text-gray-500 italic">
+                  Next: {undoDescription}
+                </p>
+              )}
+            </div>
+          )}
+        </div>
+
+        {/* Add Actors Section */}
+        <div className="border-b border-gray-200">
+          <button
+            onClick={() => toggleLeftPanelSection('addActors')}
+            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
+          >
+            <span className="text-xs font-semibold text-gray-700">Add Actors</span>
+            {leftPanelSections.addActors ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
+          </button>
+          {leftPanelSections.addActors && (
+            <div className="px-3 py-3 space-y-2">
+              {nodeTypes.map((nodeType) => (
+                <button
+                  key={nodeType.id}
+                  onClick={() => handleAddNode(nodeType.id)}
+                  className="w-full flex items-center space-x-3 px-3 py-2.5 text-sm font-medium text-white rounded hover:opacity-90 transition-opacity focus:outline-none focus:ring-2 focus:ring-offset-2 shadow-sm"
+                  style={{ backgroundColor: nodeType.color }}
+                  title={nodeType.description}
+                >
+                  <div
+                    className="w-3 h-3 rounded-full border-2 border-white"
+                    style={{ backgroundColor: nodeType.color }}
+                  />
+                  <span className="flex-1 text-left">{nodeType.label}</span>
+                </button>
+              ))}
+              <p className="text-xs text-gray-500 pt-2 border-t border-gray-100">
+                Click a button to add an actor to the canvas
+              </p>
+            </div>
+          )}
+        </div>
+
+        {/* Relations Section */}
+        <div className="border-b border-gray-200">
+          <button
+            onClick={() => toggleLeftPanelSection('relations')}
+            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
+          >
+            <span className="text-xs font-semibold text-gray-700">Relations</span>
+            {leftPanelSections.relations ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
+          </button>
+          {leftPanelSections.relations && (
+            <div className="px-3 py-3 space-y-2">
+              <label className="block text-xs font-medium text-gray-600 mb-1">
+                Active Type
+              </label>
+              <select
+                value={selectedRelationType || ''}
+                onChange={(e) => setSelectedRelationType(e.target.value)}
+                className="w-full px-3 py-2 text-sm border border-gray-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500"
+                style={{
+                  borderLeftWidth: '4px',
+                  borderLeftColor: selectedEdgeTypeConfig?.color || '#6b7280'
+                }}
+              >
+                {edgeTypes.map((edgeType) => (
+                  <option key={edgeType.id} value={edgeType.id}>
+                    {edgeType.label}
+                  </option>
+                ))}
+              </select>
+              <p className="text-xs text-gray-500 pt-1">
+                Drag from actor handles to create relations
+              </p>
+            </div>
+          )}
+        </div>
+
+        {/* Layout Section */}
+        <div className="border-b border-gray-200">
+          <button
+            onClick={() => toggleLeftPanelSection('layout')}
+            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
+          >
+            <span className="text-xs font-semibold text-gray-700">Layout</span>
+            {leftPanelSections.layout ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
+          </button>
+          {leftPanelSections.layout && (
+            <div className="px-3 py-3">
+              <p className="text-xs text-gray-500 italic">
+                Auto-layout features coming soon
+              </p>
+            </div>
+          )}
+        </div>
+
+        {/* View Section */}
+        <div className="border-b border-gray-200">
+          <button
+            onClick={() => toggleLeftPanelSection('view')}
+            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
+          >
+            <span className="text-xs font-semibold text-gray-700">View</span>
+            {leftPanelSections.view ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
+          </button>
+          {leftPanelSections.view && (
+            <div className="px-3 py-3">
+              <p className="text-xs text-gray-500 italic">
+                View options coming soon
+              </p>
+            </div>
+          )}
+        </div>
+
+        {/* Search Section */}
+        <div className="border-b border-gray-200">
+          <button
+            onClick={() => toggleLeftPanelSection('search')}
+            className="w-full px-3 py-2 flex items-center justify-between bg-gray-50 hover:bg-gray-100 transition-colors"
+          >
+            <span className="text-xs font-semibold text-gray-700">Search & Filter</span>
+            {leftPanelSections.search ? <ExpandLessIcon fontSize="small" /> : <ExpandMoreIcon fontSize="small" />}
+          </button>
+          {leftPanelSections.search && (
+            <div className="px-3 py-3">
+              <p className="text-xs text-gray-500 italic">
+                Search features coming soon
+              </p>
+            </div>
+          )}
+        </div>
+      </div>
+    </div>
+  );
+};
+
+export default LeftPanel;

src/components/Panels/RightPanel.tsx

@@ -0,0 +1,492 @@
+import { useState, useEffect, useRef, useCallback } from 'react';
+import { IconButton, Tooltip } from '@mui/material';
+import ChevronLeftIcon from '@mui/icons-material/ChevronLeft';
+import ChevronRightIcon from '@mui/icons-material/ChevronRight';
+import DeleteIcon from '@mui/icons-material/Delete';
+import { usePanelStore } from '../../stores/panelStore';
+import { useGraphWithHistory } from '../../hooks/useGraphWithHistory';
+import { useConfirm } from '../../hooks/useConfirm';
+import type { Actor, Relation } from '../../types';
+
+/**
+ * RightPanel - Context-aware properties panel on the right side
+ *
+ * Features:
+ * - Shows properties of selected node(s) or edge(s)
+ * - Live property updates (no save button)
+ * - Connection information for actors
+ * - Multi-selection support
+ * - Non-modal design (doesn't block graph view)
+ * - Collapsible
+ */
+
+interface Props {
+  selectedNode: Actor | null;
+  selectedEdge: Relation | null;
+  onClose: () => void;
+}
+
+const RightPanel = ({ selectedNode, selectedEdge, onClose }: Props) => {
+
+  const {
+    rightPanelCollapsed,
+    rightPanelWidth,
+    collapseRightPanel,
+    expandRightPanel,
+  } = usePanelStore();
+
+  const { nodeTypes, edgeTypes, updateNode, updateEdge, deleteNode, deleteEdge, edges } = useGraphWithHistory();
+  const { confirm, ConfirmDialogComponent } = useConfirm();
+
+  // Node property states
+  const [actorType, setActorType] = useState('');
+  const [actorLabel, setActorLabel] = useState('');
+  const [actorDescription, setActorDescription] = useState('');
+  const labelInputRef = useRef<HTMLInputElement>(null);
+
+  // Edge property states
+  const [relationType, setRelationType] = useState('');
+  const [relationLabel, setRelationLabel] = useState('');
+
+  // Track if user has made changes
+  const [hasNodeChanges, setHasNodeChanges] = useState(false);
+  const [hasEdgeChanges, setHasEdgeChanges] = useState(false);
+
+  // Update state when selected node changes
+  useEffect(() => {
+    if (selectedNode) {
+      setActorType(selectedNode.data?.type || '');
+      setActorLabel(selectedNode.data?.label || '');
+      setActorDescription(selectedNode.data?.description || '');
+      setHasNodeChanges(false);
+
+      // Focus and select the label input when node is selected
+      setTimeout(() => {
+        if (labelInputRef.current && !rightPanelCollapsed) {
+          labelInputRef.current.focus();
+          labelInputRef.current.select();
+        }
+      }, 100);
+    }
+  }, [selectedNode, rightPanelCollapsed]);
+
+  // Update state when selected edge changes
+  useEffect(() => {
+    if (selectedEdge && selectedEdge.data) {
+      setRelationType(selectedEdge.data.type || '');
+      const typeLabel = edgeTypes.find((et) => et.id === selectedEdge.data?.type)?.label;
+      const hasCustomLabel = selectedEdge.data.label && selectedEdge.data.label !== typeLabel;
+      setRelationLabel((hasCustomLabel && selectedEdge.data.label) || '');
+      setHasEdgeChanges(false);
+    }
+  }, [selectedEdge, edgeTypes]);
+
+  // Live update node properties (debounced)
+  const updateNodeProperties = useCallback(() => {
+    if (!selectedNode || !hasNodeChanges) return;
+    updateNode(selectedNode.id, {
+      data: {
+        type: actorType,
+        label: actorLabel,
+        description: actorDescription || undefined,
+      },
+    });
+    setHasNodeChanges(false);
+  }, [selectedNode, actorType, actorLabel, actorDescription, hasNodeChanges, updateNode]);
+
+  // Live update edge properties (debounced)
+  const updateEdgeProperties = useCallback(() => {
+    if (!selectedEdge || !hasEdgeChanges) return;
+    updateEdge(selectedEdge.id, {
+      type: relationType,
+      label: relationLabel.trim() || undefined,
+    });
+    setHasEdgeChanges(false);
+  }, [selectedEdge, relationType, relationLabel, hasEdgeChanges, updateEdge]);
+
+  // Debounce live updates
+  useEffect(() => {
+    const timeoutId = setTimeout(() => {
+      if (hasNodeChanges) {
+        updateNodeProperties();
+      }
+      if (hasEdgeChanges) {
+        updateEdgeProperties();
+      }
+    }, 500); // 500ms debounce
+
+    return () => clearTimeout(timeoutId);
+  }, [hasNodeChanges, hasEdgeChanges, updateNodeProperties, updateEdgeProperties]);
+
+  // Handle node deletion
+  const handleDeleteNode = async () => {
+    if (!selectedNode) return;
+    const confirmed = await confirm({
+      title: 'Delete Actor',
+      message: 'Are you sure you want to delete this actor? All connected relations will also be deleted.',
+      confirmLabel: 'Delete',
+      severity: 'danger',
+    });
+    if (confirmed) {
+      deleteNode(selectedNode.id);
+      onClose();
+    }
+  };
+
+  // Handle edge deletion
+  const handleDeleteEdge = async () => {
+    if (!selectedEdge) return;
+    const confirmed = await confirm({
+      title: 'Delete Relation',
+      message: 'Are you sure you want to delete this relation?',
+      confirmLabel: 'Delete',
+      severity: 'danger',
+    });
+    if (confirmed) {
+      deleteEdge(selectedEdge.id);
+      onClose();
+    }
+  };
+
+  // Get connections for selected node
+  const getNodeConnections = () => {
+    if (!selectedNode) return [];
+    return edges.filter(
+      (edge) => edge.source === selectedNode.id || edge.target === selectedNode.id
+    );
+  };
+
+  const selectedNodeTypeConfig = nodeTypes.find((nt) => nt.id === actorType);
+  const selectedEdgeTypeConfig = edgeTypes.find((et) => et.id === relationType);
+
+  // Collapsed view
+  if (rightPanelCollapsed) {
+    return (
+      <div className="h-full bg-gray-50 border-l border-gray-200 flex flex-col items-center py-2" style={{ width: '40px' }}>
+        <Tooltip title="Expand Properties Panel (Ctrl+I)" placement="left">
+          <IconButton size="small" onClick={expandRightPanel}>
+            <ChevronLeftIcon fontSize="small" />
+          </IconButton>
+        </Tooltip>
+        {ConfirmDialogComponent}
+      </div>
+    );
+  }
+
+  // No selection state
+  if (!selectedNode && !selectedEdge) {
+    return (
+      <div
+        className="h-full bg-white border-l border-gray-200 flex flex-col"
+        style={{ width: `${rightPanelWidth}px` }}
+      >
+        {/* Header */}
+        <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
+          <h2 className="text-sm font-semibold text-gray-700">Properties</h2>
+          <Tooltip title="Collapse Panel (Ctrl+I)">
+            <IconButton size="small" onClick={collapseRightPanel}>
+              <ChevronRightIcon fontSize="small" />
+            </IconButton>
+          </Tooltip>
+        </div>
+
+        {/* Empty state */}
+        <div className="flex-1 flex items-center justify-center px-4">
+          <div className="text-center text-gray-400">
+            <p className="text-sm font-medium">No Selection</p>
+            <p className="text-xs mt-1">
+              Select an actor or relation to view properties
+            </p>
+          </div>
+        </div>
+        {ConfirmDialogComponent}
+      </div>
+    );
+  }
+
+  // Node properties view
+  if (selectedNode) {
+    const connections = getNodeConnections();
+
+    return (
+      <div
+        className="h-full bg-white border-l border-gray-200 flex flex-col"
+        style={{ width: `${rightPanelWidth}px` }}
+      >
+        {/* Header */}
+        <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
+          <h2 className="text-sm font-semibold text-gray-700">Actor Properties</h2>
+          <div className="flex items-center space-x-1">
+            <Tooltip title="Close (Esc)">
+              <IconButton size="small" onClick={onClose}>
+                ✕
+              </IconButton>
+            </Tooltip>
+            <Tooltip title="Collapse Panel (Ctrl+I)">
+              <IconButton size="small" onClick={collapseRightPanel}>
+                <ChevronRightIcon fontSize="small" />
+              </IconButton>
+            </Tooltip>
+          </div>
+        </div>
+
+        {/* Scrollable content */}
+        <div className="flex-1 overflow-y-auto overflow-x-hidden px-3 py-3 space-y-4">
+          {/* Actor Type */}
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Actor Type
+            </label>
+            <select
+              value={actorType}
+              onChange={(e) => {
+                setActorType(e.target.value);
+                setHasNodeChanges(true);
+              }}
+              className="w-full px-3 py-2 text-sm border border-gray-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500"
+            >
+              {nodeTypes.map((nodeType) => (
+                <option key={nodeType.id} value={nodeType.id}>
+                  {nodeType.label}
+                </option>
+              ))}
+            </select>
+            {selectedNodeTypeConfig && (
+              <div
+                className="mt-2 h-8 rounded border-2 flex items-center justify-center text-xs font-medium text-white"
+                style={{
+                  backgroundColor: selectedNodeTypeConfig.color,
+                  borderColor: selectedNodeTypeConfig.color,
+                }}
+              >
+                {selectedNodeTypeConfig.label}
+              </div>
+            )}
+          </div>
+
+          {/* Actor Label */}
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Label *
+            </label>
+            <input
+              ref={labelInputRef}
+              type="text"
+              value={actorLabel}
+              onChange={(e) => {
+                setActorLabel(e.target.value);
+                setHasNodeChanges(true);
+              }}
+              placeholder="Enter actor name"
+              className="w-full px-3 py-2 text-sm border border-gray-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500"
+            />
+          </div>
+
+          {/* Description */}
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Description (optional)
+            </label>
+            <textarea
+              value={actorDescription}
+              onChange={(e) => {
+                setActorDescription(e.target.value);
+                setHasNodeChanges(true);
+              }}
+              placeholder="Add a description"
+              rows={3}
+              className="w-full px-3 py-2 text-sm border border-gray-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500 resize-none"
+            />
+          </div>
+
+          {/* Connections */}
+          <div className="pt-3 border-t border-gray-200">
+            <h3 className="text-xs font-semibold text-gray-700 mb-2">
+              Connections ({connections.length})
+            </h3>
+            {connections.length === 0 ? (
+              <p className="text-xs text-gray-500 italic">No connections</p>
+            ) : (
+              <div className="space-y-1">
+                {connections.map((edge) => {
+                  const edgeConfig = edgeTypes.find((et) => et.id === edge.data?.type);
+                  const isOutgoing = edge.source === selectedNode.id;
+                  const otherId = isOutgoing ? edge.target : edge.source;
+
+                  return (
+                    <div
+                      key={edge.id}
+                      className="text-xs text-gray-600 flex items-center space-x-1"
+                    >
+                      <span
+                        className="inline-block w-2 h-2 rounded-full"
+                        style={{ backgroundColor: edgeConfig?.color || '#6b7280' }}
+                      />
+                      <span className="font-medium">{edgeConfig?.label || 'Unknown'}</span>
+                      <span>{isOutgoing ? '→' : '←'}</span>
+                      <span className="text-gray-500">{otherId}</span>
+                    </div>
+                  );
+                })}
+              </div>
+            )}
+          </div>
+
+          {/* Node Info */}
+          <div className="pt-3 border-t border-gray-200">
+            <p className="text-xs text-gray-500">
+              <span className="font-medium">Node ID:</span> {selectedNode.id}
+            </p>
+            <p className="text-xs text-gray-500 mt-1">
+              <span className="font-medium">Position:</span> ({Math.round(selectedNode.position.x)}, {Math.round(selectedNode.position.y)})
+            </p>
+          </div>
+        </div>
+
+        {/* Footer with actions */}
+        <div className="px-3 py-3 border-t border-gray-200 bg-gray-50">
+          <button
+            onClick={handleDeleteNode}
+            className="w-full flex items-center justify-center space-x-2 px-3 py-2 text-sm font-medium text-white bg-red-600 hover:bg-red-700 rounded focus:outline-none focus:ring-2 focus:ring-red-500 transition-colors"
+          >
+            <DeleteIcon fontSize="small" />
+            <span>Delete Actor</span>
+          </button>
+          {hasNodeChanges && (
+            <p className="text-xs text-gray-500 mt-2 text-center italic">
+              Saving changes...
+            </p>
+          )}
+        </div>
+        {ConfirmDialogComponent}
+      </div>
+    );
+  }
+
+  // Edge properties view
+  if (selectedEdge) {
+    const renderStylePreview = () => {
+      if (!selectedEdgeTypeConfig) return null;
+
+      const strokeDasharray = {
+        solid: '0',
+        dashed: '8,4',
+        dotted: '2,4',
+      }[selectedEdgeTypeConfig.style || 'solid'];
+
+      return (
+        <svg width="100%" height="20" className="mt-2">
+          <line
+            x1="0"
+            y1="10"
+            x2="100%"
+            y2="10"
+            stroke={selectedEdgeTypeConfig.color}
+            strokeWidth="3"
+            strokeDasharray={strokeDasharray}
+          />
+        </svg>
+      );
+    };
+
+    return (
+      <div
+        className="h-full bg-white border-l border-gray-200 flex flex-col"
+        style={{ width: `${rightPanelWidth}px` }}
+      >
+        {/* Header */}
+        <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
+          <h2 className="text-sm font-semibold text-gray-700">Relation Properties</h2>
+          <div className="flex items-center space-x-1">
+            <Tooltip title="Close (Esc)">
+              <IconButton size="small" onClick={onClose}>
+                ✕
+              </IconButton>
+            </Tooltip>
+            <Tooltip title="Collapse Panel (Ctrl+I)">
+              <IconButton size="small" onClick={collapseRightPanel}>
+                <ChevronRightIcon fontSize="small" />
+              </IconButton>
+            </Tooltip>
+          </div>
+        </div>
+
+        {/* Scrollable content */}
+        <div className="flex-1 overflow-y-auto overflow-x-hidden px-3 py-3 space-y-4">
+          {/* Relation Type */}
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Relation Type
+            </label>
+            <select
+              value={relationType}
+              onChange={(e) => {
+                setRelationType(e.target.value);
+                setHasEdgeChanges(true);
+              }}
+              className="w-full px-3 py-2 text-sm border border-gray-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500"
+            >
+              {edgeTypes.map((edgeType) => (
+                <option key={edgeType.id} value={edgeType.id}>
+                  {edgeType.label}
+                </option>
+              ))}
+            </select>
+            {renderStylePreview()}
+          </div>
+
+          {/* Custom Label */}
+          <div>
+            <label className="block text-xs font-medium text-gray-700 mb-1">
+              Custom Label (optional)
+            </label>
+            <input
+              type="text"
+              value={relationLabel}
+              onChange={(e) => {
+                setRelationLabel(e.target.value);
+                setHasEdgeChanges(true);
+              }}
+              placeholder={selectedEdgeTypeConfig?.label || 'Enter label'}
+              className="w-full px-3 py-2 text-sm border border-gray-300 rounded focus:outline-none focus:ring-2 focus:ring-blue-500"
+            />
+            <p className="text-xs text-gray-500 mt-1">
+              Leave empty to use default type label
+            </p>
+          </div>
+
+          {/* Connection Info */}
+          <div className="pt-3 border-t border-gray-200">
+            <p className="text-xs text-gray-500">
+              <span className="font-medium">From:</span> {selectedEdge.source}
+            </p>
+            <p className="text-xs text-gray-500 mt-1">
+              <span className="font-medium">To:</span> {selectedEdge.target}
+            </p>
+          </div>
+        </div>
+
+        {/* Footer with actions */}
+        <div className="px-3 py-3 border-t border-gray-200 bg-gray-50">
+          <button
+            onClick={handleDeleteEdge}
+            className="w-full flex items-center justify-center space-x-2 px-3 py-2 text-sm font-medium text-white bg-red-600 hover:bg-red-700 rounded focus:outline-none focus:ring-2 focus:ring-red-500 transition-colors"
+          >
+            <DeleteIcon fontSize="small" />
+            <span>Delete Relation</span>
+          </button>
+          {hasEdgeChanges && (
+            <p className="text-xs text-gray-500 mt-2 text-center italic">
+              Saving changes...
+            </p>
+          )}
+        </div>
+        {ConfirmDialogComponent}
+      </div>
+    );
+  }
+
+  return null;
+};
+
+export default RightPanel;

src/hooks/useDocumentHistory.ts

@@ -51,15 +51,40 @@ export function useDocumentHistory() {
         return;
       }
 
-      const currentDoc = getActiveDocument();
-      if (!currentDoc) {
-        console.warn('Active document not loaded');
-        return;
-      }
-
       // Read current state directly from store (not from React hooks which might be stale)
       const currentState = useGraphStore.getState();
 
+      const currentDoc = getActiveDocument();
+      if (!currentDoc) {
+        console.warn('Active document not loaded, attempting to use current graph state');
+        // If document isn't loaded yet, create a minimal snapshot from current state
+        const snapshot: ConstellationDocument = createDocument(
+          currentState.nodes as never[],
+          currentState.edges as never[],
+          currentState.nodeTypes,
+          currentState.edgeTypes
+        );
+
+        // Use minimal metadata
+        snapshot.metadata = {
+          documentId: activeDocumentId,
+          title: 'Untitled',
+          version: '1.0.0',
+          appName: 'Constellation Analyzer',
+          createdAt: new Date().toISOString(),
+          updatedAt: new Date().toISOString(),
+          lastSavedBy: 'user',
+        };
+
+        // Push to history
+        historyStore.pushAction(activeDocumentId, {
+          description,
+          timestamp: Date.now(),
+          documentState: snapshot,
+        });
+        return;
+      }
+
       // Create a snapshot of the current state
       const snapshot: ConstellationDocument = createDocument(
         currentState.nodes as never[],

src/stores/panelStore.ts

@@ -0,0 +1,137 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+
+/**
+ * Panel Store - Manages state of collapsible side panels
+ *
+ * Features:
+ * - Left panel (tools) visibility and width
+ * - Right panel (properties) visibility and width
+ * - Panel state persistence to localStorage
+ * - Collapsed section state within panels
+ */
+
+interface PanelState {
+  // Left Panel
+  leftPanelVisible: boolean;
+  leftPanelWidth: number;
+  leftPanelCollapsed: boolean;
+  leftPanelSections: {
+    history: boolean;
+    addActors: boolean;
+    relations: boolean;
+    layout: boolean;
+    view: boolean;
+    search: boolean;
+  };
+
+  // Right Panel
+  rightPanelVisible: boolean;
+  rightPanelWidth: number;
+  rightPanelCollapsed: boolean;
+
+  // Actions
+  toggleLeftPanel: () => void;
+  toggleRightPanel: () => void;
+  setLeftPanelWidth: (width: number) => void;
+  setRightPanelWidth: (width: number) => void;
+  toggleLeftPanelSection: (section: keyof PanelState['leftPanelSections']) => void;
+  collapseLeftPanel: () => void;
+  expandLeftPanel: () => void;
+  collapseRightPanel: () => void;
+  expandRightPanel: () => void;
+}
+
+const DEFAULT_LEFT_WIDTH = 280;
+const DEFAULT_RIGHT_WIDTH = 320;
+const MIN_LEFT_WIDTH = 240;
+const MAX_LEFT_WIDTH = 400;
+const MIN_RIGHT_WIDTH = 280;
+const MAX_RIGHT_WIDTH = 500;
+const COLLAPSED_LEFT_WIDTH = 40;
+
+export const usePanelStore = create<PanelState>()(
+  persist(
+    (set) => ({
+      // Initial state
+      leftPanelVisible: true,
+      leftPanelWidth: DEFAULT_LEFT_WIDTH,
+      leftPanelCollapsed: false,
+      leftPanelSections: {
+        history: true,
+        addActors: true,
+        relations: true,
+        layout: false,
+        view: false,
+        search: false,
+      },
+
+      rightPanelVisible: true,
+      rightPanelWidth: DEFAULT_RIGHT_WIDTH,
+      rightPanelCollapsed: false,
+
+      // Actions
+      toggleLeftPanel: () =>
+        set((state) => ({
+          leftPanelVisible: !state.leftPanelVisible,
+        })),
+
+      toggleRightPanel: () =>
+        set((state) => ({
+          rightPanelVisible: !state.rightPanelVisible,
+        })),
+
+      setLeftPanelWidth: (width: number) =>
+        set(() => ({
+          leftPanelWidth: Math.max(MIN_LEFT_WIDTH, Math.min(MAX_LEFT_WIDTH, width)),
+        })),
+
+      setRightPanelWidth: (width: number) =>
+        set(() => ({
+          rightPanelWidth: Math.max(MIN_RIGHT_WIDTH, Math.min(MAX_RIGHT_WIDTH, width)),
+        })),
+
+      toggleLeftPanelSection: (section) =>
+        set((state) => ({
+          leftPanelSections: {
+            ...state.leftPanelSections,
+            [section]: !state.leftPanelSections[section],
+          },
+        })),
+
+      collapseLeftPanel: () =>
+        set(() => ({
+          leftPanelCollapsed: true,
+        })),
+
+      expandLeftPanel: () =>
+        set(() => ({
+          leftPanelCollapsed: false,
+        })),
+
+      collapseRightPanel: () =>
+        set(() => ({
+          rightPanelCollapsed: true,
+        })),
+
+      expandRightPanel: () =>
+        set(() => ({
+          rightPanelCollapsed: false,
+        })),
+    }),
+    {
+      name: 'constellation-panel-state',
+    }
+  )
+);
+
+// Export constants for use in components
+export const PANEL_CONSTANTS = {
+  DEFAULT_LEFT_WIDTH,
+  DEFAULT_RIGHT_WIDTH,
+  MIN_LEFT_WIDTH,
+  MAX_LEFT_WIDTH,
+  MIN_RIGHT_WIDTH,
+  MAX_RIGHT_WIDTH,
+  COLLAPSED_LEFT_WIDTH,
+};