0.10.4: button still-frames render only on their own state

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/CanvasStage.vue

@@ -13,7 +13,7 @@ import {
   PhTrash,
 } from '@phosphor-icons/vue'
 import { useSceneStore } from '@/stores/scene'
-import { isLayerActiveAt, sampleLayer } from '@/lib/interpolate'
+import { isButtonLayerActiveAt, isLayerActiveAt, sampleLayer } from '@/lib/interpolate'
 import { importImageFile, loadImage } from '@/lib/fileLoader'
 import { useClipartStore } from '@/stores/clipart'
 import { drawButtonFrame, drawSceneFrame, loadSceneImages } from '@/lib/render'
@@ -501,6 +501,9 @@ function buttonStackForTime(
   const layers = asset.layers.slice().reverse()
   for (const l of layers) {
     if (!l.visible) continue
+    // Button-state visibility: still-frame kfs render only on their
+    // own state, not held into neighbouring states.
+    if (!isButtonLayerActiveAt(l, stateTime)) continue
     const a = assetMap.value.get(l.assetId)
     if (!a) continue
     out.push({ layer: l, asset: a, props: sampleLayer(l, stateTime) })
@@ -754,7 +757,9 @@ function applyLivePose(props: AnimatableProps, layerId: string): AnimatableProps
 const stackItems = computed<StackItem[]>(() => {
   // Button-asset edit: show only the active state's layer stack. In the
   // 'hit' cell show the normal state's layers as an onion-skin
-  // underneath the hit-area gizmos.
+  // underneath the hit-area gizmos. Visibility follows the
+  // button-specific rule: a still-frame kf renders only on its own
+  // state, not held into subsequent states.
   if (store.activeButtonAssetId) {
     const out: StackItem[] = []
     const ba = store.activeButtonAsset
@@ -764,6 +769,7 @@ const stackItems = computed<StackItem[]>(() => {
     for (const layer of layers) {
       if (!layer.visible) continue
       if (layer.editorHidden) continue
+      if (!isButtonLayerActiveAt(layer, store.playhead)) continue
       const asset = assetMap.value.get(layer.assetId)
       if (!asset) continue
       const props = applyLivePose(sampleLayer(layer, store.playhead), layer.id)