diff --git a/frontend/src/app/pages/Dashboard/hooks/interaction/useCanvasControls.ts b/frontend/src/app/pages/Dashboard/hooks/interaction/useCanvasControls.ts
index e098fb11..0e82d496 100644
--- a/frontend/src/app/pages/Dashboard/hooks/interaction/useCanvasControls.ts
+++ b/frontend/src/app/pages/Dashboard/hooks/interaction/useCanvasControls.ts
@@ -481,6 +481,10 @@ export function useCanvasControls(
   }, [enabled, applyLive, commitLive]);
 
   const handleMouseDown = useCallback((e: React.MouseEvent) => {
+    // Portaled children (MuiDialog/Menu opened from canvas-hosted components) bubble through the REACT
+    // tree, not the DOM: without this guard their clicks started a canvas pan and the preventDefault
+    // killed input focus (the "can't click into the Add-connector fields" bug).
+    if (e.currentTarget instanceof Node && e.target instanceof Node && !e.currentTarget.contains(e.target)) return;
     e.preventDefault();
     cancelAnimation();
     cancelInertia();