Dear Britgirl,
I’ve noticed that problem occurs with all applications I’ve tested: Notes, TextEdit and Brave Browser.
I’ve also verified that the problem occurs the same way with the following combinations:
viewport + windowed mode
viewport + fullscreen
scaled + windowed mode
scaled + fullscreen
I’ve noticed that the problem goes away if I use the mouse to switch to another application and switch back to the application where I want to select something. Then if I start typing in that application, the mouse cursor disappears and when I start moving the mouse again, the mouse cursor appears again and the odd selection behavior comes back again.
Best regards,
Aleksander KorzyĆski