From ab12e72cc52e3fd9b0045fa2263ee97264c4affb Mon Sep 17 00:00:00 2001
From: Andrey Bochkarev <50177704+octaviusz@users.noreply.github.com>
Date: Sun, 25 Jan 2026 16:57:12 +0300
Subject: [PATCH] fix: Prevent sidebar from flickering when moving a tab,
 p=#12016

---
 src/zen/compact-mode/ZenCompactMode.mjs | 4 ++++
 src/zen/drag-and-drop/ZenDragAndDrop.js | 6 +++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/zen/compact-mode/ZenCompactMode.mjs b/src/zen/compact-mode/ZenCompactMode.mjs
index 8a9314ca5..575fdbbe0 100644
--- a/src/zen/compact-mode/ZenCompactMode.mjs
+++ b/src/zen/compact-mode/ZenCompactMode.mjs
@@ -743,6 +743,10 @@ window.gZenCompactModeManager = {
             return;
           }
 
+          if (this._isTabBeingDragged) {
+            return;
+          }
+
           if (this.hoverableElements[i].keepHoverDuration) {
             this.flashElement(
               target,
diff --git a/src/zen/drag-and-drop/ZenDragAndDrop.js b/src/zen/drag-and-drop/ZenDragAndDrop.js
index 11f1bb10e..aef279221 100644
--- a/src/zen/drag-and-drop/ZenDragAndDrop.js
+++ b/src/zen/drag-and-drop/ZenDragAndDrop.js
@@ -105,7 +105,7 @@
 
     startTabDrag(event, tab, ...args) {
       this.ZenDragAndDropService.onDragStart(1);
-
+      gZenCompactModeManager._isTabBeingDragged = true;
       super.startTabDrag(event, tab, ...args);
       const dt = event.dataTransfer;
       if (isTabGroupLabel(tab)) {
@@ -874,6 +874,10 @@
         this._tempDragImageParent.remove();
         delete this._tempDragImageParent;
       }
+      delete gZenCompactModeManager._isTabBeingDragged;
+      if (dt.dropEffect !== "move") {
+        gZenCompactModeManager._clearAllHoverStates();
+      }
     }
 
     #applyDragOverBackground(element) {