Running KDE on Mint, plugging a monitor into my netbook. In the KDE display settings, I have no problems positioning one monitor above or below the other, but it fails when I try to put one to the left or right. The screens go black, I can see my mouse cursor and can move it left and right between monitors, but the selection times out and reverts to previous setting. What gives?
Yes that is how it is suppose to work. If you accept the settings than will use that as default.
What I was pointing out just because the screens are black doesn't necessarily mean they aren't working. It may be they need new wallpaper assigned to the screens. As you say you can see and use the mouse during those 30seconds? .