SUMMARY
Selecting a colour in the Advanced Colour Selector causes the canvas to stop responding to tablet events.

After selecting a colour, the mouse cursor shows over the canvas instead of the brush cursor and the canvas doesn't respond to the stylus touching. Hitting ESC or refocusing the window usually alleviates the problem until the next selection.

Not Present in 4.1.7.101
Present in 4.1.8
Present in Git, 4.2.0-pre-alpha (git d2edbba)


STEPS TO REPRODUCE
1. Select colour from Advanced Colour Selector using tablet.
2. Hover over the canvas and check the cursor type.
3. Try to make a brush stroke, which should fail to register.
4. Hit ESC and try to make a brush stroke again, which should succeed.


SOFTWARE/OS VERSIONS
Linux: Arch
KDE Plasma Version: 5.15.2-1
KDE Frameworks Version: 5.55.0-1
Qt Version: 5.12.1-2

ADDITIONAL INFORMATION
Wacom Intuos 3, Xorg, AMDGPU