Firefox icon theme changes are not applied consistently across all locations

kkp — Sat, 01 Aug 2026 02:09:42 GMT

Description:
After changing the Firefox icon theme to Kit in Settings → Appearance, I noticed that the icon update is incomplete. Only the Firefox icon in the taskbar changes to the Kit icon, while other Firefox icons remain unchanged.

The issue appears in the following locations:

The Firefox icon in the taskbar is successfully changed to the Kit icon.
The Firefox desktop shortcut icon does not change and still shows the default Firefox icon.
The Firefox logo on the New Tab page remains unchanged.
The Firefox branding/icon displayed in tabs is not updated.
The Firefox icon in Private Browsing mode still uses the default icon.

This results in inconsistent Firefox branding across different parts of the system and affects the overall visual experience.

Steps to Reproduce:

Open Firefox.
Go to Settings → Appearance.
Change the application icon theme to Kit.
Restart Firefox.
Check the Firefox icons in the taskbar, desktop shortcut, New Tab page, tabs, and Private Browsing mode.

Actual Result:
Only the taskbar icon is updated to the Kit theme. Other Firefox icons continue using the default icon.

Expected Result:
When changing the Firefox icon theme, the new icon should be applied consistently to all Firefox-related locations, including:

Desktop shortcut icon;
Taskbar icon;
Firefox logo on the New Tab page;
Firefox icon/branding in tabs;
Private Browsing mode icon.

Environment Information:

Firefox Version: _154.0b5 (64 bit)___
Operating System: Windows 11
Selected Icon Theme: Kit
Firefox restarted after changing the icon: Yes

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Firefox icon theme changes are not applied consistently across all locations