Hi,

I've been having this problem for a long time now. It recently got worse.
When I disconnect the external monitor, the disconnection is detected but the screen will be distorted afterwards. These distortions vary with plasma versions. The screen may be stretched or shifted or both. The mouse stays in it's correct place, which makes it hard to click anywhere since objects on screen are not in their correct positions.
Now recently, the same problem occurs when I connect the external monitor, not only when I disconnect it.
Disabling and enabling compositing fixes the issue, but only when GLX is selected as an OpenGL interface. If EGL is selected, the screen will go back to being distorted when compositing is turned on again. I figured that out just now, so I could live with it since I don't have to restart X anymore - but it's still annoying. I guess I could write a script that disables and enables compositing - but that's more of a dirty workaround.
Is anyone else having this issue? KDE4 just flickered a bit and then it was fine. I've had this problem with every version of Plasma 5 and Frameworks so far.

Cheers,
Malte

I've seen this: I'm blaming the driver, but at the moment I've only seen it with intel (I don't have any other hardware that can be used to reproduce this issue).

Can you file an issue on bugs.kde.org?

Actually, this seems to have been fixed in Plasma 5.3, while still present in 5.2.95. I'll file a bug if it shows up again.