This page tracks the Wayland showstoppers throughout the stack. Showstoppers are major bugs, or missing features affecting the Wayland session but not the X11 session. This is part of KDE's Wayland goal.

True Showstoppers

These are the issues that must be fixed before we can recommend Wayland by default.

Session management

Applications don't prompt to save unsaved work, causing data loss: https://bugs.kde.org/show_bug.cgi?id=461176
No session restore for native Wayland windows: https://bugs.kde.org/show_bug.cgi?id=436318. Our session management recovery engine is based on the X Session Management Protocol and there is apparently currently no generic concept to do it on Wayland. But on Qt it's plugin-able and GNOME has had their own implementation for some time.

KWin/compositing/window management

When the compositor crashes or restarts, non-Qt apps are killed — work is ongoing to fix this, see https://invent.kde.org/plasma/kwin/-/wikis/Restarting
Not all Sticky Keys options work: https://bugs.kde.org/show_bug.cgi?id=444335
Windows marked "keep on top" cover up panel widget pop-ups and clipboard history menu: https://bugs.kde.org/show_bug.cgi?id=466844

Plasma

XEmbedSNIProxy window eats input in top-left pixel of the screen: https://bugs.kde.org/show_bug.cgi?id=433079
Global Menu is broken for non-Qt apps: https://bugs.kde.org/show_bug.cgi?id=424485
When dragging images from Firefox to the desktop, have to hold the drag 1 or more seconds over the desktop before releasing or else the desktop drop menu does not appear: https://bugs.kde.org/show_bug.cgi?id=448867

Upstream issues, or KDE issues blocked by required upstream changes

No color management or support for changing Gamma: https://bugs.kde.org/show_bug.cgi?id=439135, https://bugs.kde.org/show_bug.cgi?id=439135, https://invent.kde.org/plasma/kwin/-/issues/11; requires https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/14 and adoption in KWin
Picture-in-Picture windows from web browsers get a Task Manager icon and do not stay on top: https://bugs.kde.org/show_bug.cgi?id=463288; requires https://gitlab.freedesktop.org/wayland/wayland-protocols/-/merge_requests/132 and adoption in apps using PiP windows (like web browsers)
QDockWidget does not visually move when moving and is not re-dockable when detached: https://bugreports.qt.io/browse/QTBUG-87332

Specifically NVIDIA issues

Sometimes Plasma fails to launch with Wayland and NVidia (kwin_scene_opengl: Creating the OpenGL rendering failed: "query surface failed"): https://bugs.kde.org/show_bug.cgi?id=440397
Plasma Panels sometime visually freeze: https://bugs.kde.org/show_bug.cgi?id=469016
All screen content freezes when Night Color is activated: https://bugs.kde.org/show_bug.cgi?id=468895
Also Night Color just doesn't work at all on Plasma Wayland with NVIDIA: https://bugs.kde.org/show_bug.cgi?id=450327
Ghost trails/graphical glitches when waking from sleep: https://bugs.kde.org/show_bug.cgi?id=440397
After waking NVIDIA-GPU-using system from sleep, sometimes text is partially or entirely missing from from QtQuick-based apps: https://bugs.kde.org/show_bug.cgi?id=451293

Non-showstoppers

Quality-of-life issues, annoyances, problems with workarounds, etc.

Installed Chrome apps are grouped together with Chrome windows in Icon-Only Task Manager: https://bugs.kde.org/show_bug.cgi?id=358277
Multiple Chrome windows on different virtual desktops causes heavy stuttering/freezing in Chrome. Does not occur if the multiple windows are on the same virtual desktop. Similar bug report filed for Ubuntu/Gnome/Wayland here: https://bugs.launchpad.net/ubuntu/+source/xwayland/+bug/1906792
When using a Chromium-based browser in native Wayland mode, dragging an image to the desktop creates a sticky note out of it: https://bugs.kde.org/show_bug.cgi?id=449645
Session-restores window sgo on the wrong screens and virtual desktops: https://bugs.kde.org/show_bug.cgi?id=468252 + https://bugs.kde.org/show_bug.cgi?id=421870
Maximized XWayland apps leave pixel gaps when using a fractional scaling factor: https://bugs.kde.org/show_bug.cgi?id=459373
Visual line glitches with certain fractional scale factors: https://bugs.kde.org/show_bug.cgi?id=465158
Wrong app icon in Task Switcher for LibreOffice apps: https://bugreports.qt.io/browse/QTBUG-77182
Some text copied from PDFs in Okular can't be pasted once Okular quits: https://bugs.kde.org/show_bug.cgi?id=468422

Fixed upstream in Qt 6

These are fixed in Qt 6 but not backportable or backported to Qt 5.

plasmashell crashes when hovering or clicking items on the Panel due to "zwp_linux_buffer_params_v1.add" protocol error: https://bugs.kde.org/show_bug.cgi?id=447717; fixed in Qt 6.3
Wrong positioning of context menu in multiple screens: https://bugs.kde.org/show_bug.cgi?id=436016 / https://bugreports.qt.io/browse/QTBUG-85297; fixed in Qt 6.4
When using a fractional scale factor, native Wayland apps are slightly blurry: https://bugs.kde.org/show_bug.cgi?id=446674; fixed in Qt 6.6
Changing scale causes Qt-based software to become blurry until restarted: https://bugreports.qt.io/browse/QTBUG-78327; fixed in Qt 6.6
Apps using QDesktopServices::openUrl()/Qt.openUrlExternally don't raise existing windows in the activated app: https://codereview.qt-project.org/c/qt/qtwayland/+/321246 and https://codereview.qt-project.org/c/qt/qtbase/+/447556; fixed in Qt 6.5
QMenus appear as standalone windows when opened using a stylus: https://bugreports.qt.io/browse/QTBUG-111130; fixed in Qt 6.6 - https://github.com/qt/qtwayland/commit/59fae923d72eaf640035237ae6ddb1ccfeba2210
When the compositor crashes or restarts, Qt apps are killed - Fixed in Qt 6.5
In multi-monitor setups with at least one scaled display, Context menus have items which are invisible until hovered: https://bugreports.qt.io/browse/QTBUG-93380 - Fixed in Qt 6.6