diff --git a/src/components/graph/vueNodes/NodeWidgets.vue b/src/components/graph/vueNodes/NodeWidgets.vue
index 30e766da2..aa60ea0c9 100644
--- a/src/components/graph/vueNodes/NodeWidgets.vue
+++ b/src/components/graph/vueNodes/NodeWidgets.vue
@@ -123,12 +123,11 @@ const simplifiedWidget = (widget: SafeWidgetData): SimplifiedWidget => {
 
 // Handle widget value updates
 const handleWidgetUpdate = (widget: SafeWidgetData, value: unknown) => {
-  widget.value = value
-
+  // Call LiteGraph callback to update the authoritative state
+  // The callback will trigger the chained callback in useGraphNodeManager
+  // which will update the Vue state automatically
   if (widget.callback) {
     widget.callback(value)
   }
-
-  // TODO: Implement proper widget change handling to sync back to LiteGraph
 }
 </script>
diff --git a/src/components/graph/vueWidgets/WidgetInputText.vue b/src/components/graph/vueWidgets/WidgetInputText.vue
index 462957335..0c648d927 100644
--- a/src/components/graph/vueWidgets/WidgetInputText.vue
+++ b/src/components/graph/vueWidgets/WidgetInputText.vue
@@ -3,7 +3,12 @@
     <label v-if="widget.name" class="text-sm opacity-80">{{
       widget.name
     }}</label>
-    <InputText v-model="value" v-bind="filteredProps" :disabled="readonly" />
+    <InputText 
+      v-model="localValue" 
+      v-bind="filteredProps" 
+      :disabled="readonly"
+      @update:model-value="onChange" 
+    />
   </div>
 </template>
 
@@ -16,14 +21,25 @@ import {
   INPUT_EXCLUDED_PROPS,
   filterWidgetProps
 } from '@/utils/widgetPropFilter'
-
-const value = defineModel<string>({ required: true })
+import { useStringWidgetValue } from '@/composables/graph/useWidgetValue'
 
 const props = defineProps<{
   widget: SimplifiedWidget<string>
+  modelValue: string
   readonly?: boolean
 }>()
 
+const emit = defineEmits<{
+  'update:modelValue': [value: string]
+}>()
+
+// Use the composable for consistent widget value handling
+const { localValue, onChange } = useStringWidgetValue(
+  props.widget,
+  props.modelValue,
+  emit
+)
+
 const filteredProps = computed(() =>
   filterWidgetProps(props.widget.options, INPUT_EXCLUDED_PROPS)
 )
diff --git a/src/components/graph/vueWidgets/WidgetSelect.vue b/src/components/graph/vueWidgets/WidgetSelect.vue
index 2639c2e64..fd6ad317c 100644
--- a/src/components/graph/vueWidgets/WidgetSelect.vue
+++ b/src/components/graph/vueWidgets/WidgetSelect.vue
@@ -4,10 +4,11 @@
       widget.name
     }}</label>
     <Select
-      v-model="value"
+      v-model="localValue"
       :options="selectOptions"
       v-bind="filteredProps"
       :disabled="readonly"
+      @update:model-value="onChange"
     />
   </div>
 </template>
@@ -21,14 +22,26 @@ import {
   PANEL_EXCLUDED_PROPS,
   filterWidgetProps
 } from '@/utils/widgetPropFilter'
-
-const value = defineModel<any>({ required: true })
+import { useWidgetValue } from '@/composables/graph/useWidgetValue'
 
 const props = defineProps<{
   widget: SimplifiedWidget<any>
+  modelValue: any
   readonly?: boolean
 }>()
 
+const emit = defineEmits<{
+  'update:modelValue': [value: any]
+}>()
+
+// Use the composable for consistent widget value handling
+const { localValue, onChange } = useWidgetValue({
+  widget: props.widget,
+  modelValue: props.modelValue,
+  defaultValue: props.widget.options?.values?.[0] || '',
+  emit
+})
+
 const filteredProps = computed(() =>
   filterWidgetProps(props.widget.options, PANEL_EXCLUDED_PROPS)
 )
diff --git a/src/components/graph/vueWidgets/WidgetSlider.vue b/src/components/graph/vueWidgets/WidgetSlider.vue
index e7f2ece3e..f34ad04e2 100644
--- a/src/components/graph/vueWidgets/WidgetSlider.vue
+++ b/src/components/graph/vueWidgets/WidgetSlider.vue
@@ -3,7 +3,12 @@
     <label v-if="widget.name" class="text-sm opacity-80">{{
       widget.name
     }}</label>
-    <Slider v-model="value" v-bind="filteredProps" :disabled="readonly" />
+    <Slider 
+      v-model="localValue" 
+      v-bind="filteredProps" 
+      :disabled="readonly"
+      @update:model-value="onChange" 
+    />
   </div>
 </template>
 
@@ -16,14 +21,25 @@ import {
   STANDARD_EXCLUDED_PROPS,
   filterWidgetProps
 } from '@/utils/widgetPropFilter'
-
-const value = defineModel<number>({ required: true })
+import { useNumberWidgetValue } from '@/composables/graph/useWidgetValue'
 
 const props = defineProps<{
   widget: SimplifiedWidget<number>
+  modelValue: number
   readonly?: boolean
 }>()
 
+const emit = defineEmits<{
+  'update:modelValue': [value: number]
+}>()
+
+// Use the composable for consistent widget value handling
+const { localValue, onChange } = useNumberWidgetValue(
+  props.widget,
+  props.modelValue,
+  emit
+)
+
 const filteredProps = computed(() =>
   filterWidgetProps(props.widget.options, STANDARD_EXCLUDED_PROPS)
 )
diff --git a/src/components/graph/vueWidgets/WidgetToggleSwitch.vue b/src/components/graph/vueWidgets/WidgetToggleSwitch.vue
index e74203b7c..1d2733fec 100644
--- a/src/components/graph/vueWidgets/WidgetToggleSwitch.vue
+++ b/src/components/graph/vueWidgets/WidgetToggleSwitch.vue
@@ -3,7 +3,12 @@
     <label v-if="widget.name" class="text-sm opacity-80">{{
       widget.name
     }}</label>
-    <ToggleSwitch v-model="value" v-bind="filteredProps" :disabled="readonly" />
+    <ToggleSwitch 
+      v-model="localValue" 
+      v-bind="filteredProps" 
+      :disabled="readonly"
+      @update:model-value="onChange" 
+    />
   </div>
 </template>
 
@@ -16,14 +21,25 @@ import {
   STANDARD_EXCLUDED_PROPS,
   filterWidgetProps
 } from '@/utils/widgetPropFilter'
-
-const value = defineModel<boolean>({ required: true })
+import { useBooleanWidgetValue } from '@/composables/graph/useWidgetValue'
 
 const props = defineProps<{
   widget: SimplifiedWidget<boolean>
+  modelValue: boolean
   readonly?: boolean
 }>()
 
+const emit = defineEmits<{
+  'update:modelValue': [value: boolean]
+}>()
+
+// Use the composable for consistent widget value handling
+const { localValue, onChange } = useBooleanWidgetValue(
+  props.widget,
+  props.modelValue,
+  emit
+)
+
 const filteredProps = computed(() =>
   filterWidgetProps(props.widget.options, STANDARD_EXCLUDED_PROPS)
 )
diff --git a/src/composables/graph/useGraphNodeManager.ts b/src/composables/graph/useGraphNodeManager.ts
index 31970f487..99fd4536a 100644
--- a/src/composables/graph/useGraphNodeManager.ts
+++ b/src/composables/graph/useGraphNodeManager.ts
@@ -4,7 +4,7 @@
  */
 import type { LGraph, LGraphNode } from '@comfyorg/litegraph'
 import { nextTick, reactive, readonly } from 'vue'
-import { useChainCallback } from '@/composables/functional/useChainCallback'
+import { QuadTree, type Bounds } from '@/utils/spatial/QuadTree'
 
 export interface NodeState {
   visible: boolean
@@ -51,6 +51,13 @@ export interface VueNodeData {
   outputs?: unknown[]
 }
 
+export interface SpatialMetrics {
+  strategy: 'linear' | 'quadtree'
+  queryTime: number
+  nodesInIndex: number
+  threshold: number
+}
+
 export interface GraphNodeManager {
   // Reactive state - safe data extracted from LiteGraph nodes
   vueNodeData: ReadonlyMap<string, VueNodeData>
@@ -73,8 +80,15 @@ export interface GraphNodeManager {
   forceSync(): void
   detectChangesInRAF(): void
 
+  // Spatial queries
+  getVisibleNodeIds(viewportBounds: Bounds): Set<string>
+
   // Performance
   performanceMetrics: PerformanceMetrics
+  spatialMetrics: SpatialMetrics
+  
+  // Debug
+  getSpatialIndexDebugInfo(): any | null
 }
 
 export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
@@ -106,6 +120,23 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
     adaptiveQuality: false
   })
 
+  // Spatial indexing for large graphs (auto-enables at 100+ nodes)
+  const SPATIAL_INDEX_THRESHOLD = 100
+  const spatialIndex = new QuadTree<string>(
+    { x: -10000, y: -10000, width: 20000, height: 20000 },
+    { maxDepth: 6, maxItemsPerNode: 4 }
+  )
+  let spatialIndexEnabled = false
+  let lastSpatialQueryTime = 0
+
+  // Spatial metrics
+  const spatialMetrics = reactive<SpatialMetrics>({
+    strategy: 'linear',
+    queryTime: 0,
+    nodesInIndex: 0,
+    threshold: SPATIAL_INDEX_THRESHOLD
+  })
+
   // FPS tracking state
   let lastFrameTime = performance.now()
   let frameCount = 0
@@ -228,13 +259,24 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
     const nodeId = String(node.id)
     
     node.widgets?.forEach(widget => {
-      widget.callback = useChainCallback(widget.callback, () => {
+      // Create a new callback that updates the widget value AND the Vue state
+      const originalCallback = widget.callback
+      widget.callback = (value: string | number | boolean | object | undefined, ...args: unknown[]) => {
+        // 1. Update the widget value in LiteGraph
+        widget.value = value
+        
+        // 2. Call the original callback if it exists
+        if (originalCallback) {
+          originalCallback.call(widget, value as Parameters<typeof originalCallback>[0], ...args)
+        }
+        
+        // 3. Update Vue state
         try {
           const currentData = vueNodeData.get(nodeId)
           if (currentData?.widgets) {
             const updatedWidgets = currentData.widgets.map(w => 
               w.name === widget.name 
-                ? { ...w, value: widget.value }
+                ? { ...w, value: value }
                 : w
             )
             vueNodeData.set(nodeId, { 
@@ -246,7 +288,7 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
         } catch (error) {
           console.warn(`[useGraphNodeManager] Failed to update Vue state for widget ${widget.name}:`, error)
         }
-      })
+      }
     })
   }
 
@@ -363,6 +405,41 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
   }
 
   // Most performant: Direct position sync without re-setting entire node
+  // Query visible nodes using spatial index when available
+  const getVisibleNodeIds = (viewportBounds: Bounds): Set<string> => {
+    const startTime = performance.now()
+    
+    let visibleIds: Set<string>
+    
+    if (spatialIndexEnabled) {
+      // Use QuadTree for fast spatial query
+      const results = spatialIndex.query(viewportBounds)
+      visibleIds = new Set(results)
+    } else {
+      // Use simple linear search for small graphs
+      visibleIds = new Set<string>()
+      for (const [id, pos] of nodePositions) {
+        const size = nodeSizes.get(id)
+        if (!size) continue
+        
+        // Simple bounds check
+        if (!(
+          pos.x + size.width < viewportBounds.x ||
+          pos.x > viewportBounds.x + viewportBounds.width ||
+          pos.y + size.height < viewportBounds.y ||
+          pos.y > viewportBounds.y + viewportBounds.height
+        )) {
+          visibleIds.add(id)
+        }
+      }
+    }
+    
+    lastSpatialQueryTime = performance.now() - startTime
+    spatialMetrics.queryTime = lastSpatialQueryTime
+    
+    return visibleIds
+  }
+
   const detectChangesInRAF = () => {
     const startTime = performance.now()
     
@@ -371,12 +448,27 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
     let positionUpdates = 0
     let sizeUpdates = 0
 
+    // Check if we should enable/disable spatial indexing
+    const nodeCount = graph._nodes.length
+    const shouldUseSpatialIndex = nodeCount >= SPATIAL_INDEX_THRESHOLD
+    
+    if (shouldUseSpatialIndex !== spatialIndexEnabled) {
+      spatialIndexEnabled = shouldUseSpatialIndex
+      if (!spatialIndexEnabled) {
+        spatialIndex.clear()
+      }
+      spatialMetrics.strategy = spatialIndexEnabled ? 'quadtree' : 'linear'
+    }
+
     // Update reactive positions and sizes
     for (const node of graph._nodes) {
       const id = String(node.id)
       const currentPos = nodePositions.get(id)
       const currentSize = nodeSizes.get(id)
 
+      let posChanged = false
+      let sizeChanged = false
+
       if (
         !currentPos ||
         currentPos.x !== node.pos[0] ||
@@ -384,6 +476,7 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
       ) {
         nodePositions.set(id, { x: node.pos[0], y: node.pos[1] })
         positionUpdates++
+        posChanged = true
       }
 
       if (
@@ -393,6 +486,18 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
       ) {
         nodeSizes.set(id, { width: node.size[0], height: node.size[1] })
         sizeUpdates++
+        sizeChanged = true
+      }
+
+      // Update spatial index if enabled and position/size changed
+      if (spatialIndexEnabled && (posChanged || sizeChanged)) {
+        const bounds: Bounds = {
+          x: node.pos[0],
+          y: node.pos[1],
+          width: node.size[0],
+          height: node.size[1]
+        }
+        spatialIndex.update(id, bounds)
       }
     }
 
@@ -403,6 +508,7 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
     performanceMetrics.culledCount = Array.from(nodeState.values()).filter(
       state => state.culled
     ).length
+    spatialMetrics.nodesInIndex = spatialIndexEnabled ? spatialIndex.size : 0
     
     if (positionUpdates > 0 || sizeUpdates > 0) {
       performanceMetrics.rafUpdateCount++
@@ -421,8 +527,11 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
 
       // Store non-reactive reference to original node
       nodeRefs.set(id, node)
+      
+      // Set up widget callbacks BEFORE extracting data
+      setupNodeWidgetCallbacks(node)
 
-      // Extract safe data for Vue
+      // Extract safe data for Vue (now with proper callbacks)
       vueNodeData.set(id, extractVueNodeData(node))
 
       // Set up reactive tracking
@@ -436,7 +545,16 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
       nodeSizes.set(id, { width: node.size[0], height: node.size[1] })
       attachMetadata(node)
       
-      setupNodeWidgetCallbacks(node)
+      // Add to spatial index if enabled
+      if (spatialIndexEnabled) {
+        const bounds: Bounds = {
+          x: node.pos[0],
+          y: node.pos[1],
+          width: node.size[0],
+          height: node.size[1]
+        }
+        spatialIndex.insert(id, bounds, id)
+      }
       
       if (originalOnNodeAdded) {
         void originalOnNodeAdded(node)
@@ -445,6 +563,12 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
 
     graph.onNodeRemoved = (node: LGraphNode) => {
       const id = String(node.id)
+      
+      // Remove from spatial index if enabled
+      if (spatialIndexEnabled) {
+        spatialIndex.remove(id)
+      }
+      
       nodeRefs.delete(id)
       vueNodeData.delete(id)
       nodeState.delete(id)
@@ -485,6 +609,7 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
       pendingUpdates.clear()
       criticalUpdates.clear()
       lowPriorityUpdates.clear()
+      spatialIndex.clear()
     }
   }
 
@@ -508,6 +633,9 @@ export const useGraphNodeManager = (graph: LGraph): GraphNodeManager => {
     scheduleUpdate,
     forceSync: syncWithGraph,
     detectChangesInRAF,
-    performanceMetrics
+    getVisibleNodeIds,
+    performanceMetrics,
+    spatialMetrics: readonly(spatialMetrics),
+    getSpatialIndexDebugInfo: () => spatialIndexEnabled ? spatialIndex.getDebugInfo() : null
   }
 }
diff --git a/src/composables/graph/useWidgetValue.ts b/src/composables/graph/useWidgetValue.ts
new file mode 100644
index 000000000..3a61952f5
--- /dev/null
+++ b/src/composables/graph/useWidgetValue.ts
@@ -0,0 +1,138 @@
+/**
+ * Composable for managing widget value synchronization between Vue and LiteGraph
+ * Provides consistent pattern for immediate UI updates and LiteGraph callbacks
+ */
+import { ref, watch, type Ref } from 'vue'
+import type { SimplifiedWidget } from '@/types/simplifiedWidget'
+
+export interface UseWidgetValueOptions<T, U = T> {
+  /** The widget configuration from LiteGraph */
+  widget: SimplifiedWidget<T>
+  /** The current value from parent component */
+  modelValue: T
+  /** Default value if modelValue is null/undefined */
+  defaultValue: T
+  /** Emit function from component setup */
+  emit: (event: 'update:modelValue', value: T) => void
+  /** Optional value transformer before sending to LiteGraph */
+  transform?: (value: U) => T
+}
+
+export interface UseWidgetValueReturn<T, U = T> {
+  /** Local value for immediate UI updates */
+  localValue: Ref<T>
+  /** Handler for user interactions */
+  onChange: (newValue: U) => void
+}
+
+/**
+ * Manages widget value synchronization with LiteGraph
+ * 
+ * @example
+ * ```vue
+ * const { localValue, onChange } = useWidgetValue({
+ *   widget: props.widget,
+ *   modelValue: props.modelValue,
+ *   defaultValue: ''
+ * })
+ * ```
+ */
+export function useWidgetValue<T, U = T>({
+  widget,
+  modelValue,
+  defaultValue,
+  emit,
+  transform
+}: UseWidgetValueOptions<T, U>): UseWidgetValueReturn<T, U> {
+  // Local value for immediate UI updates
+  const localValue = ref<T>(modelValue ?? defaultValue)
+
+  // Handle user changes
+  const onChange = (newValue: U) => {
+    // Handle different PrimeVue component signatures
+    let processedValue: T
+    if (transform) {
+      processedValue = transform(newValue)
+    } else {
+      processedValue = newValue as unknown as T
+    }
+    
+    // 1. Update local state for immediate UI feedback
+    localValue.value = processedValue
+    
+    // 2. Emit to parent component
+    emit('update:modelValue', processedValue)
+    
+    // 3. Call LiteGraph callback to update authoritative state
+    if (widget.callback) {
+      widget.callback(processedValue)
+    }
+  }
+
+  // Watch for external updates from LiteGraph
+  watch(() => modelValue, (newValue) => {
+    localValue.value = newValue ?? defaultValue
+  })
+
+  return {
+    localValue: localValue as Ref<T>,
+    onChange
+  }
+}
+
+/**
+ * Type-specific helper for string widgets
+ */
+export function useStringWidgetValue(
+  widget: SimplifiedWidget<string>,
+  modelValue: string,
+  emit: (event: 'update:modelValue', value: string) => void
+) {
+  return useWidgetValue({
+    widget,
+    modelValue,
+    defaultValue: '',
+    emit,
+    transform: (value: string | undefined) => String(value || '') // Handle undefined from PrimeVue
+  })
+}
+
+/**
+ * Type-specific helper for number widgets
+ */
+export function useNumberWidgetValue(
+  widget: SimplifiedWidget<number>,
+  modelValue: number,
+  emit: (event: 'update:modelValue', value: number) => void
+) {
+  return useWidgetValue({
+    widget,
+    modelValue,
+    defaultValue: 0,
+    emit,
+    transform: (value: number | number[]) => {
+      // Handle PrimeVue Slider which can emit number | number[]
+      if (Array.isArray(value)) {
+        return value[0] || 0
+      }
+      return Number(value) || 0
+    }
+  })
+}
+
+/**
+ * Type-specific helper for boolean widgets
+ */
+export function useBooleanWidgetValue(
+  widget: SimplifiedWidget<boolean>,
+  modelValue: boolean,
+  emit: (event: 'update:modelValue', value: boolean) => void
+) {
+  return useWidgetValue({
+    widget,
+    modelValue,
+    defaultValue: false,
+    emit,
+    transform: (value: boolean) => Boolean(value)
+  })
+}
\ No newline at end of file