1934139 - When Mica is enabled, the window minimize, maximize, and close buttons in the F11 fullscreen mode are invisible

Status: RESOLVED DUPLICATE of bug 1934040

(Core :: Widget: Win32, defect, P3)

Description

[kanapa1]

Attachment: Invisible window control buttons in the fullscreen mode

Steps to reproduce:

1. Make sure that:
   • you are using Firefox version 133 stable
   • support for the Mica effect from Windows 11 is enabled in the advanced settings via the widget.windows.mica pref
   • you are using the default theme, i.e. System theme — auto, as this is currently the only one that uses native (or at least native-looking) Windows 11 window control buttons (see bug 1934137)
     If these three conditions are met, proceed to the next step.
2. Start Firefox.
3. Switch to the browser's fullscreen mode by pressing F11 on the keyboard or, alternatively, by using the application hamburger menu.
4. Move the cursor to the top of the screen to make sure the main Firefox UI is not hidden.
5. Look at the top right corner of the screen and see what is described in the "Actual results" section.

Actual results:

The window minimize, maximize, and close buttons are no longer visible. They are still there and can be clicked, but they are just invisible (see the attached screenshot).

This whole thing looks and behaves very similarly to the old bug 1825535 I reported some time ago when I was still using a machine running Windows 8.1, as well as bug 1800622, which is related to Windows 7 instead. However, I'm not sure if there's any connection between the current bug, the description of which you're currently reading, and the other two, but there might be, and that's why I mention it.

Expected results:

The window control buttons in the F11 fullscreen mode should not only be there but also clearly visible to the user.

Comment 1

[Emilio Cobos Álvarez [:emilio]]

Yes, there is. With mica, we need to show the native minimize / maximize / close buttons, afaict (which is really silly, but I haven't found a way of making DWM not draw them without breaking things like Win11 Snap Layouts, help welcome there, see bug 1934040).

Edge does this somehow, and there must be a lower level mechanism of making the DWM titlebar taller (here).

But I haven't found a way of either:

• Removing the caption buttons without side effects like breaking snap layouts.
• Making DWM draw the buttons of the right height.

The ideal thing would be the former. That way we can just draw our own buttons like everywhere else.

Comment 2

[Emilio Cobos Álvarez [:emilio]]

(Shuffling a bit all the mica bugs to have them tracked consistently)

Comment 3

[Emilio Cobos Álvarez [:emilio]]

The right fix for this basically depends on how we manage to go about bug 1934040:

• If we manage to hide the DWM titlebar, then we just remove the CSS mentioned in bug 1934040 comment 0 and everything gets automatically fixed.
• If we can't, and we grow the DWM titlebar instead, the CSS in bug 1934040 comment 0 needs an extra tweak to not do it in fullscreen.

Comment 4

[Emilio Cobos Álvarez [:emilio]]

Bug 1934040 fixes this.