GTK3 Client‑Side Decorations Not Considered

[7enderhead]

Before filing a bug report...

• I have checked the FAQ
• I have searched for existing open bugs
• I have confirmed the bug exists on the github main 2026-05-27

Describe the bug
Windows which use _GTK_FRAME_EXTENTS are not positioned flush.

Reproduction Instructions...

1. Focus a window which uses _GTK_FRAME_EXTENTS
2. Tile to any side
3. _GTK_FRAME_EXTENTS are considered for alignment, so alignment is not flush to side of monitor
4. Evince PDF reader is an example for that
5. example screenshot and debug output is for command "right"

Debug Output:

DEBUG: Executing command 'right' with arguments (), {}
DEBUG: Gathering usable areas manually...
DEBUG: Loaded monitor geometry: [Rectangle(x=1200, y=0, width=2560, height=1440), Rectangle(x=0, y=20, width=1200, height=1920)]
DEBUG: Gathered _NET_WM_STRUT_PARTIAL value: [StrutPartial(left=1222, right=0, top=0, bottom=0, left_start_y=0, left_end_y=1439, right_start_y=0, right_end_y=0, top_start_x=0, top_end_x=0, bottom_start_x=0, bottom_end_x=0)]
DEBUG: Usable desktop region calculated as: Region(<Monitors=[Rectangle(x=1200, y=0, width=2560, height=1440), Rectangle(x=0, y=20, width=1200, height=1920)], Struts=[StrutPartial(left=1222, right=0, top=0, bottom=0, left_start_y=0, left_end_y=1439, right_start_y=0, right_end_y=0, top_start_x=0, top_end_x=0, bottom_start_x=0, bottom_end_x=0)]>)
DEBUG: Operating on window <Wnck.Window object at 0x7fc657663580 (WnckWindow at 0x92445f0)> with title "my.pdf" and geometry Rectangle(x=1222, y=0, width=1258, height=1440)
DEBUG:  Window is on monitor 0, which has geometry Rectangle(x=1200, y=0, width=2560, height=1440)
DEBUG: Selected preset sequence:
        ((0.5, 0.0, 0.5, 1.0), (0.8, 0.0, 0.2, 1.0), (0.6, 0.0, 0.4, 1.0), (0.4, 0.0, 0.6, 1.0), (0.2, 0.0, 0.8, 1.0))
DEBUG: Selected preset sequence resolves to these monitor-relative pixel dimensions:
        [Rectangle(x=1280, y=0, width=1280, height=1440), Rectangle(x=2048, y=0, width=512, height=1440), Rectangle(x=1536, y=0, width=1024, height=1440), Rectangle(x=1024, y=0, width=1536, height=1440), Rectangle(x=512, y=0, width=2048, height=1440)]
DEBUG: Got saved cycle position: 3, 0
DEBUG: Target preset is Rectangle(x=2480, y=0, width=1280, height=1440) relative to monitor Rectangle(x=1200, y=0, width=2560, height=1440)
DEBUG: Calling reposition() with default gravity and dimensions Rectangle(x=2480, y=0, width=1280, height=1440)
DEBUG:  Window is on monitor 0, which has geometry Rectangle(x=1200, y=0, width=2560, height=1440)
DEBUG:  Repositioning to Rectangle(x=2480, y=0, width=1280, height=1440))

[ssokolow]

Thanks. Just be aware that this may take a while since, even more so than some of the other open issues, I'm not currently set up to reproduce and test it conveniently, and I have higher priority issues to resolve first.

(I'm a KDE user and my response to things like Headerbars and the impending GTK4 font blur on non-HiDPI displays has been to work toward having a GTK-free desktop.)