Minimizing UE4

I dont know if its just me but whenever i have UE4 minimised for a long time, it wont maximise again and doesnt respond. To solve this i have to close it via task manager. Is this an ongoing bug?

This seams like a bug, I recommend you to post this in the bug report section.
Also how much RAM does your system have.

Ive got 16GB 1333Mhz