I'm not sure which update did it - but at some point recently something broke my Desktop. I now have a grey background (instead of the gradient colour I had before) and no Desktop icons. Right clicking on the Desktop doesn't produce a menu any more, either.

My theme, sounds etc all seem to have been forcibly changed as well.

Also, when I attempt to start Phpstorm, it hangs on the splashscreen, and console shows:

Error parsing gtk-icon-sizes string: ''

Anyone have a suggestion how I fix it, or even diagnose what the problem is?