fix: hide empty actionbar container and relocate error border to floating actionbar (#9657)

## Summary
When the actionbar is floating and has no docked buttons, the container
is now hidden (zero-width, transparent border) to avoid showing an empty
rounded box. Additionally, the error/destructive border is now applied
to the floating actionbar panel itself (via `ComfyActionbar`) instead of
the container, so it appears in the correct location when floating.

## Changes
- **TopMenuSection**: Added `hasDockedButtons` and
`isActionbarContainerEmpty` computed properties to detect when the
docked container has no visible buttons; `actionbarContainerClass`
computed hides the container by collapsing it when empty and floating,
while preserving the legacy drop zone via `:has(.border-dashed)` CSS
selector
- **TopMenuSection**: Error border
(`border-destructive-background-hover`) is now only applied to the
docked container when the actionbar is **not** floating
- **ComfyActionbar**: Accepts new `hasAnyError` prop and applies the
error border to the floating panel's `panelClass` when floating

## Review Focus
- The `has-[.border-dashed]` CSS selector restores the container visuals
when a legacy drag-target element is present inside it — verify this
works as expected
- Error border placement: docked mode shows border on container,
floating mode shows border on the fixed panel

## Screenshots


https://github.com/user-attachments/assets/75caabac-e391-4bfd-b4dc-62d564e55d37

src/components/TopMenuSection.vue

@@ -34,17 +34,7 @@
             </Button>
           </div>
 
-          <div
-            ref="actionbarContainerRef"
-            :class="
-              cn(
-                'actionbar-container pointer-events-auto relative flex h-12 items-center gap-2 rounded-lg border bg-comfy-menu-bg px-2 shadow-interface',
-                hasAnyError
-                  ? 'border-destructive-background-hover'
-                  : 'border-interface-stroke'
-              )
-            "
-          >
+          <div ref="actionbarContainerRef" :class="actionbarContainerClass">
             <ActionBarButtons />
             <!-- Support for legacy topbar elements attached by custom scripts, hidden if no elements present -->
             <div
@@ -55,6 +45,7 @@
             <ComfyActionbar
               :top-menu-container="actionbarContainerRef"
               :queue-overlay-expanded="isQueueOverlayExpanded"
+              :has-any-error="hasAnyError"
               @update:progress-target="updateProgressTarget"
             />
             <CurrentUserButton
@@ -123,7 +114,7 @@
 </template>
 
 <script setup lang="ts">
-import { useLocalStorage } from '@vueuse/core'
+import { useLocalStorage, useMutationObserver } from '@vueuse/core'
 import { storeToRefs } from 'pinia'
 import { computed, onMounted, ref } from 'vue'
 import { useI18n } from 'vue-i18n'
@@ -145,6 +136,7 @@ import { buildTooltipConfig } from '@/composables/useTooltipConfig'
 import { useSettingStore } from '@/platform/settings/settingStore'
 import { app } from '@/scripts/app'
 import { useExecutionErrorStore } from '@/stores/executionErrorStore'
+import { useActionBarButtonStore } from '@/stores/actionBarButtonStore'
 import { useQueueUIStore } from '@/stores/queueStore'
 import { useRightSidePanelStore } from '@/stores/workspace/rightSidePanelStore'
 import { useWorkspaceStore } from '@/stores/workspaceStore'
@@ -168,6 +160,7 @@ const { isLoggedIn } = useCurrentUser()
 const { t } = useI18n()
 const { toastErrorHandler } = useErrorHandling()
 const executionErrorStore = useExecutionErrorStore()
+const actionBarButtonStore = useActionBarButtonStore()
 const queueUIStore = useQueueUIStore()
 const { isOverlayExpanded: isQueueOverlayExpanded } = storeToRefs(queueUIStore)
 const { shouldShowRedDot: shouldShowConflictRedDot } =
@@ -182,6 +175,43 @@ const isActionbarEnabled = computed(
 const isActionbarFloating = computed(
   () => isActionbarEnabled.value && !isActionbarDocked.value
 )
+/**
+ * Whether the actionbar container has any visible docked buttons
+ * (excluding ComfyActionbar, which uses position:fixed when floating
+ * and does not contribute to the container's visual layout).
+ */
+const hasDockedButtons = computed(() => {
+  if (actionBarButtonStore.buttons.length > 0) return true
+  if (hasLegacyContent.value) return true
+  if (isLoggedIn.value && !isIntegratedTabBar.value) return true
+  if (isDesktop && !isIntegratedTabBar.value) return true
+  if (isCloud && flags.workflowSharingEnabled) return true
+  if (!isRightSidePanelOpen.value) return true
+  return false
+})
+const isActionbarContainerEmpty = computed(
+  () => isActionbarFloating.value && !hasDockedButtons.value
+)
+const actionbarContainerClass = computed(() => {
+  const base =
+    'actionbar-container pointer-events-auto relative flex h-12 items-center gap-2 rounded-lg border bg-comfy-menu-bg shadow-interface'
+
+  if (isActionbarContainerEmpty.value) {
+    return cn(
+      base,
+      '-ml-2 w-0 min-w-0 border-transparent shadow-none',
+      'has-[.border-dashed]:ml-0 has-[.border-dashed]:w-auto has-[.border-dashed]:min-w-auto',
+      'has-[.border-dashed]:border-interface-stroke has-[.border-dashed]:pl-2 has-[.border-dashed]:shadow-interface'
+    )
+  }
+
+  const borderClass =
+    !isActionbarFloating.value && hasAnyError.value
+      ? 'border-destructive-background-hover'
+      : 'border-interface-stroke'
+
+  return cn(base, 'px-2', borderClass)
+})
 const isIntegratedTabBar = computed(
   () => settingStore.get('Comfy.UI.TabBarLayout') !== 'Legacy'
 )
@@ -233,6 +263,25 @@ const rightSidePanelTooltipConfig = computed(() =>
 
 // Maintain support for legacy topbar elements attached by custom scripts
 const legacyCommandsContainerRef = ref<HTMLElement>()
+const hasLegacyContent = ref(false)
+
+function checkLegacyContent() {
+  const el = legacyCommandsContainerRef.value
+  if (!el) {
+    hasLegacyContent.value = false
+    return
+  }
+  // Mirror the CSS: [&:not(:has(*>*:not(:empty)))]:hidden
+  hasLegacyContent.value =
+    el.querySelector(':scope > * > *:not(:empty)') !== null
+}
+
+useMutationObserver(legacyCommandsContainerRef, checkLegacyContent, {
+  childList: true,
+  subtree: true,
+  characterData: true
+})
+
 onMounted(() => {
   if (legacyCommandsContainerRef.value) {
     app.menu.element.style.width = 'fit-content'

src/components/actionbar/ComfyActionbar.vue

@@ -119,9 +119,14 @@ import { cn } from '@/utils/tailwindUtil'
 
 import ComfyRunButton from './ComfyRunButton'
 
-const { topMenuContainer, queueOverlayExpanded = false } = defineProps<{
+const {
+  topMenuContainer,
+  queueOverlayExpanded = false,
+  hasAnyError = false
+} = defineProps<{
   topMenuContainer?: HTMLElement | null
   queueOverlayExpanded?: boolean
+  hasAnyError?: boolean
 }>()
 
 const emit = defineEmits<{
@@ -435,7 +440,12 @@ const panelClass = computed(() =>
     isDragging.value && 'pointer-events-none select-none',
     isDocked.value
       ? 'static border-none bg-transparent p-0'
-      : 'fixed shadow-interface'
+      : [
+          'fixed shadow-interface',
+          hasAnyError
+            ? 'border-destructive-background-hover'
+            : 'border-interface-stroke'
+        ]
   )
 )
 </script>