diff --git a/src/components/WorkflowCanvas.tsx b/src/components/WorkflowCanvas.tsx
index 3997177b..499696cb 100644
--- a/src/components/WorkflowCanvas.tsx
+++ b/src/components/WorkflowCanvas.tsx
@@ -98,7 +98,8 @@ const BOX_SELECTION_EXPAND_MIN_DISTANCE = 4;
 const MULTI_SELECTION_BOUNDS_PADDING = 40;
 const GROUP_NODE_Z_INDEX = 0;
 const DEFAULT_NODE_Z_INDEX = 1;
-const INITIAL_ACTIVE_NODE_Z_INDEX = 100;
+const INITIAL_TOP_STACK_Z_INDEX = 100;
+const INITIAL_TOP_MEMBER_Z_INDEX = 1;
 
 type ScreenPoint = {
   x: number;
@@ -572,10 +573,10 @@ export function WorkflowCanvas() {
   const [isMiniMapOpen, setIsMiniMapOpen] = useState(false);
   const [zoomPercent, setZoomPercent] = useState(100);
   const [draggingGroupId, setDraggingGroupId] = useState<string | null>(null);
-  const [activeNodeLayer, setActiveNodeLayer] = useState<{ nodeId: string | null; zIndex: number }>({
-    nodeId: null,
-    zIndex: INITIAL_ACTIVE_NODE_Z_INDEX,
-  });
+  const [stackLayerMap, setStackLayerMap] = useState<Record<string, number>>({});
+  const [memberLayerMap, setMemberLayerMap] = useState<Record<string, number>>({});
+  const [topStackLayer, setTopStackLayer] = useState(INITIAL_TOP_STACK_Z_INDEX);
+  const topMemberLayerRef = useRef(INITIAL_TOP_MEMBER_Z_INDEX);
   const canvasGridColor = "var(--canvas-grid)";
   const miniMapMaskColor = "var(--surface-overlay)";
   const miniMapNodeColor = "var(--text-disabled)";
@@ -588,18 +589,39 @@ export function WorkflowCanvas() {
   const gestureZoomStartRef = useRef<{ zoom: number } | null>(null);
   const [boxSelectionRect, setBoxSelectionRect] = useState<FlowRect | null>(null);
 
-  const bringNodeToFront = useCallback((nodeId: string) => {
-    setActiveNodeLayer((current) => ({
-      nodeId,
-      zIndex: current.zIndex + 1,
-    }));
-  }, []);
+  const bringNodeToFront = useCallback((node: Node) => {
+    const nodeGroupId = node.type === "group"
+      ? (node.data as { groupId?: string }).groupId
+      : (node as Node & { groupId?: string }).groupId;
+    const groupNodeId = nodeGroupId ? `group-node-${nodeGroupId}` : null;
+
+    if (node.type !== "group" && nodeGroupId && groupNodeId) {
+      topMemberLayerRef.current += 1;
+      const nextMemberLayer = topMemberLayerRef.current;
+      setMemberLayerMap((layers) => ({
+        ...layers,
+        [node.id]: nextMemberLayer,
+      }));
+
+      setTopStackLayer((current) => {
+        const nextStackLayer = current + 1;
+        setStackLayerMap((layers) => ({
+          ...layers,
+          [groupNodeId]: nextStackLayer,
+        }));
+        return nextStackLayer;
+      });
+      return;
+    }
 
-  const resetActiveNodeLayer = useCallback(() => {
-    setActiveNodeLayer((current) => ({
-      ...current,
-      nodeId: null,
-    }));
+    setTopStackLayer((current) => {
+      const nextStackLayer = current + 1;
+      setStackLayerMap((layers) => ({
+        ...layers,
+        [node.id]: nextStackLayer,
+      }));
+      return nextStackLayer;
+    });
   }, []);
 
   const onNodesChange = useCallback((changes: NodeChange<WorkflowNode>[]) => {
@@ -893,13 +915,15 @@ export function WorkflowCanvas() {
   // Apply visual state that React Flow can turn into DOM classes and z-index.
   const allNodes = useMemo(() => {
     const draggingGroupNodeId = draggingGroupId ? `group-node-${draggingGroupId}` : null;
-    const activeNode = activeNodeLayer.nodeId
-      ? nodes.find((node) => node.id === activeNodeLayer.nodeId)
-      : undefined;
-    const activeGroupId = activeNode?.type === "group"
-      ? (activeNode.data as { groupId?: string }).groupId
-      : undefined;
-    const activeGroupNodeId = activeGroupId ? `group-node-${activeGroupId}` : null;
+    const groupStackLayerById = new Map<string, number>();
+    for (const node of nodes) {
+      if (node.type !== "group") continue;
+      const groupId = (node.data as { groupId?: string }).groupId;
+      const stackLayer = stackLayerMap[node.id];
+      if (groupId && stackLayer !== undefined) {
+        groupStackLayerById.set(groupId, stackLayer);
+      }
+    }
 
     return nodes.map((node) => {
       // Never dim Switch or ConditionalSwitch nodes themselves
@@ -919,29 +943,27 @@ export function WorkflowCanvas() {
       // Preserve existing className if any, add/remove dimmed/skipped classes
       const baseClass = (node.className || "").replace(/\bswitch-dimmed\b/g, "").replace(/\bnode-skipped\b/g, "").trim();
       const newClass = extraClasses ? `${baseClass} ${extraClasses}`.trim() : baseClass;
-      let zIndex = node.type === "group" ? GROUP_NODE_Z_INDEX : DEFAULT_NODE_Z_INDEX;
-
-      if (activeGroupId && node.id === activeGroupNodeId) {
-        zIndex = activeNodeLayer.zIndex;
-      } else if (activeGroupId && node.type !== "group" && (node.groupId === activeGroupId || node.parentId === activeGroupNodeId)) {
-        zIndex = activeNodeLayer.zIndex + 1;
-      } else if (!activeGroupId && node.id === activeNodeLayer.nodeId) {
-        zIndex = activeNodeLayer.zIndex;
-      }
+      const nodeGroupId = (node as Node & { groupId?: string }).groupId;
+      const groupStackLayer = nodeGroupId ? groupStackLayerById.get(nodeGroupId) : undefined;
+      let zIndex = node.type === "group"
+        ? stackLayerMap[node.id] ?? GROUP_NODE_Z_INDEX
+        : nodeGroupId && groupStackLayer !== undefined
+        ? groupStackLayer + (memberLayerMap[node.id] ?? DEFAULT_NODE_Z_INDEX)
+        : stackLayerMap[node.id] ?? DEFAULT_NODE_Z_INDEX;
 
       if (isDraggingGroupShell) {
-        zIndex = Math.max(zIndex, activeNodeLayer.zIndex);
+        zIndex = Math.max(zIndex, topStackLayer);
       } else if (isDraggingGroupMember) {
-        zIndex = Math.max(zIndex, activeNodeLayer.zIndex + 1);
+        zIndex = Math.max(zIndex, topStackLayer + (memberLayerMap[node.id] ?? DEFAULT_NODE_Z_INDEX));
       } else if (node.dragging) {
-        zIndex = Math.max(zIndex, activeNodeLayer.zIndex + 1);
+        zIndex = Math.max(zIndex, topStackLayer + 1);
       }
 
       // Only create new node object if className changed
       if (node.className === newClass && node.zIndex === zIndex) return node;
       return { ...node, className: newClass, zIndex };
     });
-  }, [nodes, activeNodeLayer, dimmedNodeIds, draggingGroupId, skippedNodeIds]);
+  }, [nodes, dimmedNodeIds, draggingGroupId, memberLayerMap, skippedNodeIds, stackLayerMap, topStackLayer]);
 
   const absoluteNodePositions = useMemo(() => {
     const byId = new Map(allNodes.map((node) => [node.id, node]));
@@ -3078,12 +3100,12 @@ export function WorkflowCanvas() {
             onMoveStart={() => { isPanningRef.current = true; setHoveredNodeId(null); document.documentElement.classList.add("canvas-interacting"); }}
             onMoveEnd={() => { isPanningRef.current = false; document.documentElement.classList.remove("canvas-interacting"); syncZoomPercent(); }}
             onNodeClick={(_event, node) => {
-              bringNodeToFront(node.id);
+              bringNodeToFront(node);
             }}
             onNodeDragStart={(_event, node) => {
               isDraggingNodeRef.current = true;
               document.documentElement.classList.add("canvas-interacting");
-              bringNodeToFront(node.id);
+              bringNodeToFront(node);
               setDraggingGroupId(node.type === "group" ? (node.data as { groupId?: string }).groupId ?? null : null);
             }}
             onNodeDragStop={(event, node) => {
@@ -3092,7 +3114,6 @@ export function WorkflowCanvas() {
               setDraggingGroupId(null);
               handleNodeDragStop(event, node);
             }}
-            onPaneClick={resetActiveNodeLayer}
             onPaneContextMenu={openCanvasContextMenu}
             onNodeContextMenu={openNodeContextMenu}
             onSelectionStart={handleSelectionStart}