[gnome-shell] altTab: Remove down arrow when removing an app from switcher

[Florian Müllner <fmuellner src gnome org>]

commit 845122497b487860fb90f531194068876da95911
Author: Sebastian Keller <skeller gnome org>
Date:   Mon Jun 29 22:51:41 2020 +0200

    altTab: Remove down arrow when removing an app from switcher
    
    The arrow of the removed app was still left in the list with the
    visibility of the arrow still depending on the original list order. This
    could either lead to apps with just one window now suddenly having a
    down arrow or apps with multiple windows not having one. If the last
    window in the list had a down arrow, it would have been displayed
    outside the window switcher.
    
    Fixes https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/2935
    
    https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1340

 js/ui/altTab.js | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/js/ui/altTab.js b/js/ui/altTab.js
index b56cc49cf9..d637e2fbf1 100644
--- a/js/ui/altTab.js
+++ b/js/ui/altTab.js
@@ -852,6 +852,9 @@ class AppSwitcher extends SwitcherPopup.SwitcherList {
         if (index === -1)
             return;
 
+        this._arrows[index].destroy();
+        this._arrows.splice(index, 1);
+
         this.icons.splice(index, 1);
         this.removeItem(index);
     }