Created attachment 129179 [details] screenshot of my two-monitor desktop, note plain color wallpaper doesn't fill external monitor SUMMARY Upon my last two Plasma logins, my plain color desktop "wallpaper" doesn't fill my external monitor. The color fills 1920x1080 pixels of my external DisplayPort monitor, which is the size as my Thinkpad T461's built-in display, but my external monitor is 1920x1200 so there's a black strip at the bottom (see attachment). Covering the desktop with a window then exposing it doesn't fix the problem, the black repaints. The problem goes away (i.e. my chosen color fills the entire display) if I right-click "Edit..." my plasma panel. STEPS TO REPRODUCE 1. Configure Displays of laptop with external 1920x1200 monitor to have external display on top and primary monitor. 2. Right-click desktop on external monitor, choose Configure Desktop... > Desktop Settings, set layout: Desktop, Wallpaper Type: Plain Color, Color:#264c37 (dark green). I also set the same on my laptop display. 3. Restart KDE. OBSERVED RESULT Twice now after rebooting into KDE my plain wallpaper color does not extend over the entire second monitor (see attachment). EXPECTED RESULT Desktop wallpaper solid color should fill; both monitors entirely. This worked fine for years until the last week or so. Fedora 32 KDE spin updates KDE regularly, most libraries date from May 5 and some from May 18. SOFTWARE/OS VERSIONS Linux/KDE Plasma: KDE Plasma Version: 5.18.5 KDE Frameworks Version: 5.70.0 Qt Version: 5.13.2 (xcb) ADDITIONAL INFORMATION
I ran `xwininfo -tree -children -root -frame -bits` and the root window has lots of children but only three of the right width: the plasma panel, and two of the same size as my displays at the end: xwininfo: Window id: 0x7b8 (the root window) (has no name) Root window id: 0x7b8 (the root window) (has no name) Parent window id: 0x0 (none) 88 children: ... 0x24000c2 (has no name): () 1920x32+0+1168 +0+1168 1 child: 0x24000c3 (has no name): () 1920x32+0+0 +0+1168 1 child: 0x220002e "Plasma": ("plasmashell" "plasmashell") 1920x32+0+0 +0+1168 ... 0x2400062 (has no name): () 1920x1080+1+1200 +1+1200 1 child: 0x2400063 (has no name): () 1920x1080+0+0 +1+1200 1 child: 0x220001b "Desktop — Plasma": ("plasmashell" "plasmashell") 1920x1080+0+0 +1+1200 0x2400055 (has no name): () 1920x1200+0+0 +0+0 1 child: 0x2400056 (has no name): () 1920x1200+0+0 +0+0 1 child: 0x2200013 "Desktop — Plasma": ("plasmashell" "plasmashell") 1920x1200+0+0 +0+0 I notice my laptop monitor is offset 1 pixel horizontally (presumably this is why the screenshot is 1921 pixels wide), but there are child windows of the right height for my external 1900x1200 monitor. So something in kwin or plasma is telling the wallpaper to paint the wrong y dimension. Is there some way to debug this short of running my own kwin and plasmashell under gdb? E.g. run with --qmljsdebugger or some debug setting?
Can you open the context menu if you click on the black area?
(In reply to David Edmundson from comment #2) > Can you open the context menu if you click on the black area? Yes I can. The black area acts like a normal part of the desktop, just not painted with my green background color. I tried adding a second panel in the black area, but the special panel editing mode where the the regular windows vanish made the problem go away. I watched a reboot today. After logging in at the lock screen, my entire external monitor screen painted with green, then the black area appeared. At around the same time the laptop screen painted green. I'm not sure of the exact order because it happened in less than 2 seconds, but I'm pretty sure the whole external monitor painted green before the black appeared
I'm now on Plasma 5.20.4, KDE 5.75.0, Qt 5.15.2 (xcb), and for well over a month I haven't seen the black strip on my external monitor. I sometimes see a partial paint on my external monitor during KDE startup, but I end up with full solid backgrounds. So... maybe fixed? \o/ Or a timing issue that my system is now avoiding. Anyway, I resolved this WORKSFORME ; maybe FIXED is better.
Created attachment 158502 [details] same problem (that wallpaper doesn't fill external monitor) with newer Plasma
This bug has happened a few more times, most recently today, so I'm reopening. I'm now on Wayland and I don't know how to dump a window hierarchy like `xwininfo`. The one thing I did in the most recent failure was plug in the external DisplayPort monitor during boot (but long before I logged in to Plasma). Now I'm on Fedora 37, with KDE Plasma Version: 5.27.4 KDE Frameworks Version: 5.105.0 Qt Version: 5.15.9 on Wayland