Open Bug 1431555 Opened 5 years ago Updated 2 months ago

windows disappear from bad-parsing of registry hex value


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

57 Branch
Windows 10





(Reporter: geoff_groos, Unassigned)




(2 files)

Attached image actual.png
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0
Build ID: 20180103231032

Steps to reproduce:

setting `Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\DWM\ColorPrevalence` to 1, which causes any theme colors to be applied to the title bars of applications, causes firefox to render improperly and _loose track_ of windows.

to repro:
0. run on windows, x64, firefox 57.0.4
1. open regedit with admin rights
2. navigate to `Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\DWM`
3. change "ColorPrevalence" to "1".
4. run firefox, attempt window management (snap, resize, etc)

Actual results:

firefox window border & title pane is not rendered correctly.

- if multiple windows are opened, background windows will occasionally refuse to enter foreground. The only recovery is to close and re-open the window
- maximize maximizes over top of the taskbar
- snap doesnt work
- resizing doesnt work

Expected results:

 firefox renders as it would when the registry value is set to 0. Snapping, resizing, and other window management features work as they do when the registry value is set to 0.
Component: Untriaged → Theme
OS: Unspecified → Windows 10
Hardware: Unspecified → x86
What version of Windows 10 are you using? Please run winver and let me know the exact version and build ID.
Flags: needinfo?(geoff_groos)
See Also: → 1405593
Flags: needinfo?(geoff_groos)
See above screenshot:

Microsoft Windows
Version 1703 (OS Build 15063.850)
I think I've got a much more specific piece of info for you: the windowing systems parsing of the regex value appears to be bad.

If I set AccentColor to 0x00123456 then I see this bug, where 12 is R, 45 is G, and 56 is B.
If I set AccentColor to 0xFF123456 then this bug goes away. 

I'm going to upload some screenshots and change the name of this bug appropriately.
Priority: -- → P5
Summary: windows disappear when title bar is set to a specific colour on windows → windows disappear from bad-parsing of registry hex value
This is implemented here:

Presumably -moz-win-accentcolor becomes transparent here or something.
Component: Theme → Widget: Win32
Priority: P5 → --
Product: Firefox → Core
Priority: -- → P3
I can confirm this. I just came across this issue when the same thing happened to me. I followed the instructions here:

Here are .reg files that will reproduce the issue:

After setting these keys, the Firefox window doesn't display, but it shows up in the taskbar. When I hover over Firefox in the taskbar it's a small, blank placeholder window. Sometimes I can open Firefox right after signing in, but it has thick white borders on the right and left. These keys work like they are supposed to everywhere else - they change the title bar colors just fine.
See Also: → 1437329
Severity: normal → S3
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