This may be helpful in debugging this issue. I’ve been experiencing the same problem, but it actually started a few releases back. It happened very rarely then. In 2117, it happens a lot—in nearly every session. However, I have discovered that it I wait long enough the dialogs will eventually complete. Long enough being somewhere between 15 and 30 seconds, or more. I’ve also seen similar behavior with the material editor not repainting after making a change. This too will complete after a long wait. Once things appear correctly the problem seems to go away for the rest of the session.
I’m running Window 10 64 (Latest edition)