The problem persisted for two days. It was something to do with using the D, G & M keys while adjusting lines in the footprint editor, but I just couldn’t consistently replicate the problem; at least not to report a formal bug.
Now, and for the last two days, after repeated experiments, the problem has completely disappeared.
However:
Sometime, during the approximately ten crashes I had, I have lost all “layers” on my monitor except for Pads and their numbers when I open the footprint editor directly… no lines, arcs, texts, fills etc. in both my own libraries and Kicad libraries (f.silk, f.court & f.fab.)
I assumed I had just corrupted the programme with the crashes, so had waited for a new version of 5.99.
That version arrived today, dated the 4th Nov. but upon loading, didn’t fix my problem.
Any suggestions from anyone before I exterminate 5.99 and then reload it?
Also, what is the easiest way to completely and utterly remove 5.99 from Linux Mint?
It’s probably just preferences. Go to your preferences directory (it’s location will depend on platform but can be found by clicking the “Show Themes” button at the top right of one of the Colors pages in preferences).
Once you find the 5.99 directory, quit KiCad, delete everything in the directory, and then restart KiCad.