Game sometimes bugging out when selecting "Import Settings"

I was playing the Release Candidate today and I accidentally clicked on the "Import Settings" button. The file selection opened, but as soon as I pressed close, the game tabbed out. I reopened the game and the file selection was still there. It only closed when I wanted to record the bug, which lagged Minecraft.

NOTE: I forgot to include this in environment, but I was playing in fullscreen