While it is possible to enter edit mode by press-and-hold in the desktop, it is not possible to edit currently existing widgets. One would expect this functionality to be available by press-and-hold on top of each widget. This sort of functionality would also allow to remove or replace widgets, especially useful when don't have access to a mouse or touchpad, which is usually the case for tablets.
Confirmed. The mouse area that handles mouse hover seems to ignore touch taps.
A possibly relevant merge request was started @ https://invent.kde.org/plasma/plasma-desktop/-/merge_requests/541
Git commit 97add87ba49e751e62f56c03bcaa8ff58c9ad1a4 by Nate Graham. Committed on 09/08/2021 at 20:00. Pushed by ngraham into branch 'master'. [containments/panel] Fix panel applet configuration with touch Despite this UI seeming very touch-centric, it was actually totally boken for the touch use due to the use of mouse-specific code, namely setting the current applet only when the mouse moved and also hiding the tooltip when the mouse edited the area--neither of which are compatible with authentic touch events when handled by a mouse area, because the synthesized mouse position exits the mousearea as soon as the finger used to touch the screen is retracted. This is fixed by setting the current applet when clicked/touched as well, and removing the onExited signal handler to hide the tooltip, which was unnecessary anyway because the tooltip gets hidden by other things and this still works. Now touch interaction with panel applets while in panel edit mode works as expected. FIXED-IN: 5.22.5 M +12 -2 containments/panel/contents/ui/ConfigOverlay.qml https://invent.kde.org/plasma/plasma-desktop/commit/97add87ba49e751e62f56c03bcaa8ff58c9ad1a4
Git commit 78bd7883be916ff92fb6d4fc4ca18e32f4ff9e8d by Nate Graham. Committed on 09/08/2021 at 20:02. Pushed by ngraham into branch 'Plasma/5.22'. [containments/panel] Fix panel applet configuration with touch Despite this UI seeming very touch-centric, it was actually totally boken for the touch use due to the use of mouse-specific code, namely setting the current applet only when the mouse moved and also hiding the tooltip when the mouse edited the area--neither of which are compatible with authentic touch events when handled by a mouse area, because the synthesized mouse position exits the mousearea as soon as the finger used to touch the screen is retracted. This is fixed by setting the current applet when clicked/touched as well, and removing the onExited signal handler to hide the tooltip, which was unnecessary anyway because the tooltip gets hidden by other things and this still works. Now touch interaction with panel applets while in panel edit mode works as expected. FIXED-IN: 5.22.5 (cherry picked from commit 97add87ba49e751e62f56c03bcaa8ff58c9ad1a4) M +12 -2 containments/panel/contents/ui/ConfigOverlay.qml https://invent.kde.org/plasma/plasma-desktop/commit/78bd7883be916ff92fb6d4fc4ca18e32f4ff9e8d