PM stuck in taskbar

[lokiys]

I have seen This bug before.

PM just stuck in taskbar, You can not maximize it in any way.
Only can close it down with task manager.

 

[VladZen]

Was it one time glitch or it repeats?

 

[lokiys]

Was it one time glitch or it repeats?

It happens time to time.
Not very often and not sure how to reproduce.
Not version related also, as this happened before with other versions for me.