Can close all documents till a blank GUI appears.
But then neither File/Exit nor X-Button closes the GUI.
Version 18.104.22.168 (Build ID: 815c576)
22.214.171.124 (Build ID: 73f9fb6) is not affected ==> REGRESSION
from comment #2 correct status is duplicate.
*** This bug has been marked as a duplicate of bug 51659 ***