Editor frozen after closing an Editor Window

Steps to reproduce:

1. Go to File > Build Profiles
2. Select "macOS Server" in the sidebar
3. Click on "Add Build Profile"
4. Click on "Add Build Profile" at the bottom in the window that pops up
5. Go back to Build Profiles window
6. Click on "Cloud build"
7. Close the pop-up
8. Repeat 6-7 if needed to repro

Actual results: Editor freezes for a while, if you move the windows to another screen it becomes all black (see videos). In some cases the editor stays frozen (when the pop-up happens on editor refresh) otherwise it comes back after a minute or two

Expected results: 

Modal window should close and editor should be okay

Reproducible with versions: trunk

Not reproducible with versions: 

Can’t test with versions: 

Tested on (OS): mac (not tested on windows)

Notes:

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