As you know I have had this exact same issue but think I may have found the solution.
I do not have the automatic "Check for Updates" set (and usually have to update manually) but for once I pressed the Check For Updates button on the main screen. This presented me with the Essential Core Update options mentioned at https://www.ocs-support.co.uk/forums/vi ... php?t=4524.
After pressing a few buttons as directed, this carried out the update in a matter of seconds. And, hey presto, the problem has gone! The displayer now works as it should.
So do try this, Doug, to see if it works for you too.
John