I found that a Test script's content is lost when its DBMS-Output tab is cleared via the context menu (not with the button!)
(Beta 2 on windows 10 21H1 64 Bit)
I've now tested it again. In my current constellation it works.
The only changes: I'm using beta 3 and a color mode (previously with style ).
I'm sure I've made some small changes, but I can't think of anything relevant to the behavior.