I see some other similar threads on this, but the issue I'm having is a little different (although possible related).

I'm using Windows 7 64, Pl/SQL Dev 9.0.4

When I highlight SQL from the SQL window and copy it to the clipboard (Ctrl+C), the screen freezes/pauses for a few seconds.

All other programs on my PC can copy to the clipbord just fine.

Any idea of which settings/preferences I could change to stop this issue?