diff --git a/src/app/admin/ontology/ontology-graph.tsx b/src/app/admin/ontology/ontology-graph.tsx
index af5ac75..1485a41 100644
--- a/src/app/admin/ontology/ontology-graph.tsx
+++ b/src/app/admin/ontology/ontology-graph.tsx
@@ -1,6 +1,6 @@
 "use client"
 
-import { useEffect, useMemo, useRef, useState } from "react"
+import { memo, useEffect, useMemo, useRef, useState } from "react"
 import dagre from "dagre"
 import { zoom as d3Zoom, zoomIdentity, ZoomBehavior, ZoomTransform } from "d3-zoom"
 import { select as d3Select } from "d3-selection"
@@ -139,7 +139,11 @@ function edgeHierarchyPath(
   return `M ${s.x} ${s.y + NODE_HEIGHT / 2} L ${t.x} ${t.y - NODE_HEIGHT / 2}`
 }
 
-export function OntologyGraph({ schemas, edges, selectedId, onSelect, onClear, selectedEdgeType }: Props) {
+// Memoized: this renders a large SVG tree (grid + every edge, label and node),
+// so it must not re-reconcile when the parent page re-renders for unrelated
+// reasons (chat busy-state, panel toggles). It only re-renders when its own
+// props change. Keep parent-supplied handlers stable (useCallback) to preserve this.
+export const OntologyGraph = memo(function OntologyGraph({ schemas, edges, selectedId, onSelect, onClear, selectedEdgeType }: Props) {
   const svgRef = useRef<SVGSVGElement>(null)
   const zoomRef = useRef<ZoomBehavior<SVGSVGElement, unknown>>(null)
   const containerRef = useRef<SVGGElement>(null)
@@ -659,4 +663,4 @@ export function OntologyGraph({ schemas, edges, selectedId, onSelect, onClear, s
       </div>
     </div>
   )
-}
+})
diff --git a/src/app/admin/ontology/page.tsx b/src/app/admin/ontology/page.tsx
index 05697f4..6b39e1d 100644
--- a/src/app/admin/ontology/page.tsx
+++ b/src/app/admin/ontology/page.tsx
@@ -77,6 +77,9 @@ export default function OntologyPage() {
       .map(([edgeType, count]) => ({ edgeType, count }))
   }, [store.edges, edgeSearch])
 
+  // Stable so the memoized OntologyGraph doesn't re-render on unrelated page updates.
+  const handleClearSelection = useCallback(() => setSelectedId(null), [])
+
   const handleSwitchToEdges = useCallback(() => {
     setSidebarTab("edges")
     setSelectedId(null)
@@ -471,7 +474,7 @@ export default function OntologyPage() {
             edges={store.edges}
             selectedId={selectedId}
             onSelect={setSelectedId}
-            onClear={() => setSelectedId(null)}
+            onClear={handleClearSelection}
             selectedEdgeType={selectedEdgeType}
           />
         )}