Bug 422096

STEPS TO REPRODUCE
1. Open the timeline panel (as a good example of this problem).
2. Move the mouse cursor over a layer, and press the right mouse button down.
3. Observe the context menu opens (which is wrong by Windows platform standards—it should instead open on mouse up, which would incidentally fix the bug).
4. Also observe that a fair fraction of the time it opens *with the first context menu item (New Layer) selected* (which is hopefully wrong everywhere).
5. Release the right mouse button.

OBSERVED RESULT
The action (New Layer) is performed, if the first item in the context menu is focused. (If that didn’t happen, move the mouse somewhere else and try right clicking again.)

EXPECTED RESULT
The context menu should have opened and stayed open, as I hadn’t moved the mouse at all, but just right clicked.

SOFTWARE/OS VERSIONS
Krita 4.2.9 (x64)
Windows 10
Qt 5.12.7
Hardware: Surface Book, scaling factor of 200%

ADDITIONAL INFORMATION
I suspect that the focusing of the first item in the menu occurs on high-DPI devices only, something to do with rounding of pixel positions so that in some positions it opens the menu less than one logical pixel above and to the left of the cursor, so that the when the menu opens the cursor is already hovering on the first menu item, when it should have been at least one physical pixel above and to the left of it.

This is extremely irritating because it makes right clicking unreliable. However, it can normally be worked around: most laptop touchpads will either have a physical button that you can right-click-and-hold (and then move the cursor before releasing), or have pressing in the bottom right corner of the touchpad act as the right mouse button. But I suspect there are devices out there incapable of right-click-and-hold, which would make this very bad.

On an earlier point: I know Windows conventions: all actions resulting from mouse events (e.g. click button, right click context menu, do something with dragged file, &c.) take place on mouse up, and NEVER on mouse down (I hereby deem beginning dragging something not an action; 😛). I have no idea about other platform standards, least of all KDE. I have kdenlive installed, and it opens some context menus on mouseup (e.g. timeline) and some on mousedown (e.g. project bin). Eww, such inconsistency!