Bug 513727

SUMMARY:
When triggering Overview (Meta+W) or Grid View on a 3-monitor Wayland setup with Intel Arc B580, the effect only renders correctly on the leftmost monitor. The other 2 monitors don't repaint and show stale content until another action forces a refresh.

STEPS TO REPRODUCE:
1. Have 3 monitors connected via DisplayPort (all with HDR enabled)
2. Use Wayland session
3. Press Meta+W to trigger Overview (or hot corner)
4. Observe: Only leftmost monitor shows the effect

EXPECTED BEHAVIOR:
All 3 monitors show Overview/Grid View effect simultaneously

ACTUAL BEHAVIOR:
Only one monitor renders the effect correctly. The other 2 monitors show stale/old content. Forcing a refresh (e.g., opening launcher) causes momentary flicker where the effect partially paints on other monitors before being overwritten.

RELATED ISSUE:
The "Slide" animation for virtual desktop switching has the exact same symptom - only one monitor animates. Workaround: Disabling slide animation (using "Fade" or no animation) fixes desktop switching. However, Overview/Grid View have no similar animation toggle.

SYSTEM INFORMATION:
- Plasma: 6.4.5
- KWin: 6.4.5  
- Qt: (system default)
- Kernel: 6.17.0-8-generic
- GPU: Intel Corporation Battlemage G21 [Arc B580]
- Driver: Mesa 25.2.3-1ubuntu1
- Session: Wayland
- Monitors: 3x DisplayPort at 2560x2880@60Hz (scaled 2x), HDR enabled

MONITOR LAYOUT:
- DP-3: 0,0 (leftmost, rotated) - effect WORKS here
- DP-1: 1440,0 (center)
- DP-2: 2720,0 (rightmost, rotated)

ADDITIONAL NOTES:
- Issue does NOT occur on single monitor
- Hot corner trigger has same issue
- Switching to X11 not tested