浏览器启动之后，会存在上下两个标题栏

[飞羽]

浏览器版本：firefox nightly 154.0a1（2026-06-27） 操作系统版本：windows10 家庭中文版 22h2 在第一次打开浏览器的时候，会出现两个标题栏（截图见附件），重新大小化之后重复标题栏消失。浏览器进程存在的情况下，打开第二个浏览器，不会再出现这个情况。但只要将浏览器全部关闭再启动，仍然会出现两个标题栏

[Agentvirtuel]

Hello

Yes, that's what i noticed recently too on Firefox Nightly

Bypass

Customize Firefox controls, buttons and toolbars
https://support.mozilla.org/en-US/kb/customize-firefox-controls-buttons-and-toolbars
Turn on the Title bar: Put a check mark next to Title Bar in the lower left

[Agentvirtuel]

Anyway, this Title bar, your screenshot, can not be use it

To follow the evolution of updates, the best is to customize Firefox controls, buttons and toolbars
Turn off the Title bar

[Agentvirtuel]

Apparently, a similar discussion https://bugzilla.mozilla.org/show_bug.cgi?id=2051030

[Agentvirtuel]

Hello

These similar discussions
https://support.mozilla.org/en-US/questions/1591195
https://bugzilla.mozilla.org/show_bug.cgi?id=2051611

Below, currently, Firefox Nightly Title bar