Created attachment 94226 [details] screenshot of bad state in kmines playfield 1. run kmines, start a new game 2. move the mouse cursor over a field, then press and hold the left mouse button 3. while still holding the mouse button, press Ctrl+H (show highscores) on the keyboard 4. while the highscore tables are shown, release the mouse button 5. close the highscores Now all buttons are released, but as you can see in the attached screenshot, the field that was clicked before looks like it is an empty uncovered field and cannot be fully accessed (like marking it as a mine). You can get even worse results when doing the same with the middle button: it becomes impossible to uncover anything as long as the middle mouse button has not been clicked once more. This might also be the cause to bug #284952 and bug #344894, and it might be related to bug #221725.
Thank you for reporting this bug in KDE software. As it has been a while since this issue was reported and confirmed, can we please ask you to see if you can reproduce the issue with a recent software version? If you can reproduce the issue, please change the status to "CONFIRMED" when replying. Thank you!
Problem still there in 4.0.22043, but it is mitigated: When reproducing this effect with the middle mouse button, it is now possible to uncover the individual fields by clicking on the respective field twice.
It is also possible to reproduce this behavior simply by hovering over a tile and 1. Holding left mouse button 2. Holding right mouse button 3. Releasing left mouse button 4. Releasing right mouse button It happens frequently to me while playing, probably when alternating quickly between left/right clicking.