So the title pretty much sums it up. After switching my resolution to 3840 x 2160 (which is supported on my 4k monitor), it successfully changes the resolution, but then I am unable to click on anything else. Anybody else have this problem?
Update and apparent fix:
A workaround for this 3K scaling bug (or 4k Resolution 3840x2160)
1. In the control panel under FONTS -> Change Font Size, set size to 100% (log out , log back in)
2. go back to Fonts -> Set Custom Text Size DPI to 160% or whatever works. (log out , log back in)
3. Use Space Engine!
Hope this helps others with a 3K or 4K Displays.