Bug 464167

Summary: Adding titlebar on borderless GTK subwindow puts empty gaps
Product: [I don't know] kde Reporter: David <david.cortes.rivera>
Component: generalAssignee: Unassigned bugs <unassigned-bugs-null>
Status: RESOLVED DOWNSTREAM    
Severity: normal CC: nate
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Other   
OS: Linux   
Latest Commit: Version Fixed In:
Sentry Crash Report:
Attachments: evolution_strange_border

Description David 2023-01-11 20:14:52 UTC
Created attachment 155221 [details]
evolution_strange_border

SUMMARY
If I launch evolution (GTK email client which doesn't use the regular titlebar and window buttons as most other apps) and configure the window rules to forcefully make it use a titlebar, when it opens a subwindow to reply to an email, it will add a titlebar to it, but along the way will add extra empty transparent spacing throughout all 4 borders of the window (see attached screenshot), which looks very weird, instead of just drawing the titlebar above the usual subwindow without spacing in the way.

STEPS TO REPRODUCE
1. Launch evolution.
2. Right-click the titlebar and select 'More Actions' -> tick **off** 'No Border' (alternatively, could be set to draw a titlebar in the window rules as it's currently worded a bit differently there).
3. Configure evolution to access you email.
4. Select some random email inside evolution, right-click it, and select 'Reply to Sender'.
5. Look at the borders in the newly opened subwindow.

OBSERVED RESULT
Has empty space extending across the borders, and there's a gap between the GTK-drawn subwindow and the KDE-drawn titlebar.

EXPECTED RESULT
Should put a titlebar above the GTK-drawn subwindow, without extra spaces and without having a gap between the window and the titlebar.

SOFTWARE/OS VERSIONS
Operating System: Debian GNU/Linux
KDE Plasma Version: 5.26.4
KDE Frameworks Version: 5.101.0
Qt Version: 5.15.7
Kernel Version: 5.18.0-4-amd64 (64-bit)
Graphics Platform: X11
Processors: 16 × AMD Ryzen 7 2700 Eight-Core Processor
Memory: 15.5 GiB of RAM
Graphics Processor: AMD Radeon RX Vega
Manufacturer: Acer
Product Name: Predator PH517-61
System Version: V1.09

ADDITIONAL INFORMATION
Comment 1 Nate Graham 2023-01-12 19:48:46 UTC
Unfortunately this isn't fixable. KWin asks the window how big it is, and the window tells KWin its size including its self-drawn shadow--because from that window's perspective, those area *are* a part of it, because it's responsible for drawing them.

If you want to use SSDs (server-side decorations, AKA window-manager-provided titlebar and shadow), Evolution itself needs code to enable that by disabling its own CSD stuff.