I have recently started experiencing a highly irritating problem in JOSM - objects are randomly rotated without my moving them. It appears to be occurring when I switch to another window, and causes massive damage to my map. I have been very careful to check everything is deselected when panning, scaling or rotating anything, yet the problem persists.
Comment from Luciano on 24 November 2016 at 23:13
For troubleshooting, you might look into whether it is a broken plugin. The most recent JOSM upgrade (vers. 11223) broke several plugins I had installed but wasn’t using much, including one called “areaselector” - based on that plugin’s name, if this was broken it could perhaps lead to the behavior you describe. Try cleaning up you plugins list, deselecting any that you aren’t deeply attached to using.
To be honest, though, this does not sound like a JOSM problem. I never had problems with rotating, but at the time I transitioned my primary home setup to Linux, I had some trouble with getting the wireless keyboard and mouse setup working correctly with the Linux OS, and the wonky keyboard and mouse were sending very strange commands to JOSM, among other applications. I ended up with moved and deleted random objects, but again, this wasn’t because of JOSM, it was just a keyboard problem.