Plasma/X11 Known Significant Issues

This page tracks the "Errata/Known issues" that are specific to the the Plasma X11 session: significant quality-of-life annoyances, significant problems with workarounds, etc. It is the X11-specific companion to Plasma/Wayland Known Significant Issues.

X server

• If the X server crashes, all apps are killed
• If a context menu is open, it blocks automatic screen locking and global shortcuts
• No isolation between processes; any app can spy on what other apps are doing
• No protection from malicious apps secretly recording keystrokes or the screen, etc

Multiscreen/scaling

• No support for mixed screen scale screen arrangements
• No support for mixed refresh rate screen arrangements with the compositor active
• No support for adaptive sync with multiple displays
• When screen arrangements change, Plasma and QtQuick-based apps frequently crash: https://bugs.kde.org/show_bug.cgi?id=414805 + https://bugs.kde.org/show_bug.cgi?id=473602 + https://bugs.kde.org/show_bug.cgi?id=446987 + https://bugs.kde.org/show_bug.cgi?id=456947
• With a global scale greater than 100%, maximized windows leave gaps around the edges: https://bugs.kde.org/show_bug.cgi?id=414522
• With a global scale greater than 100%, cursors, splash screens, and icons in Plasma context menus, and Plasma popup corners are too small: https://bugs.kde.org/show_bug.cgi?id=422548 + https://bugs.kde.org/show_bug.cgi?id=443607 + https://bugs.kde.org/show_bug.cgi?id=356446 + https://bugs.kde.org/show_bug.cgi?id=422559

Plasma

• Firefox and Plasma can deadlock one another and both hang when copying something to the clipboard in such a manner that also shows a notification: https://bugs.kde.org/show_bug.cgi?id=446581
• Bottoms of notification popups sometimes get cut off: https://bugs.kde.org/show_bug.cgi?id=464029
• "Keyboard layout changed" OSD does not work: https://bugs.kde.org/show_bug.cgi?id=408928

KWin/rendering/graphics

• Sometimes windows randomly turn black and freeze: https://bugs.kde.org/show_bug.cgi?id=466771
• No native touchpad gestures
• No support for GPU hot-plug
• Bad multi-gpu performance in many cases
• No support for HDR
• Apps need to opt into color management, so most look wrong on wide color gamut screens, produce screenshots and screen recordings without color profile tags etc
• Using 10 bits per color completely breaks many apps
• Increased latency and stutter with the compositor active
• No recovery from GPU resets in most cases
• No reliable way to prevent screen tearing
• Enabling adaptive sync requires editing a config file
• KWin sometimes crashes when disabling compositing: https://bugs.kde.org/show_bug.cgi?id=466380
• Touchscreen gestures eat a pixel on their screen edges, breaking Fitts' law when using a pointing device
• Sometimes Overview effect stops accepting keyboard input: https://bugs.kde.org/show_bug.cgi?id=449840
• SDDM virtual keyboard is unusably small: https://bugs.kde.org/show_bug.cgi?id=431949
• Some windows are transparent on launch, then content fills in later: https://bugs.kde.org/show_bug.cgi?id=422596
• Screen locker sometimes randomly falls back to software rendering: https://bugs.kde.org/show_bug.cgi?id=423301

NVIDIA

• When reenabling compositing, sometimes windows begin flickering and flipping upside-down: https://bugs.kde.org/show_bug.cgi?id=450301
• In Spectacle, Rectangular Region background is sometimes bleached white with certain NVIDIA GPUs: https://bugs.kde.org/show_bug.cgi?id=469022

System Settings

• Acceleration profile settings of Mouse & Touchpad KCMs are missing depending on how you open the KCM: https://bugs.kde.org/show_bug.cgi?id=448953