Application disappears unexpectedly (goes into background)

[Alan Stenhouse]

I've got a MacOS LC standalone that opens a stackfile external to the application. Whenever I click inside one of the stack windows which doesn't have current focus, all the stack windows disappear and reappear only when I switch to another application and back again. Activating a stack window by clicking on the window title bar works normally (i.e. does not disappear).

Has anyone else seen this at all? Any suggestions for tracking possible causes?

MacOS Ventura
Laptop M1
LC 10 dp... and LC9.11


Thanks a lot for any pointers!

cheers
Alan