HELP! Just upgraded client and editor acting strange

I just upgraded from Win XP to Win 7 and also upgraded to Toad For Oracle Base, 11.5.1.2. Whenever I’m in the SQL or PL/SQL editor and use the navigation keys, it is selecting text between last and new cursor positions. I have flipped every option that I can find in View > Toad Options, but cannot figure out how to disable selection by default with the navigation keys. Any guidance would sure be appreciated…