cannot drag regions
i've been working on a mix and everything was fine. i saved and closed the session and then when i opened it again later i found that i wasn't able to drag any of the regions! i can trim the regions and even nudge them from the edit menu, but i can no longer drag the regions with the select tool (hand). the tracks are behaving as if they were all locked, which they aren't.
is there something i can look for in the xml file which might've gotten discombobulated somehow? or does anyone have another idea of what might be going on here?
thanks in advance for any help!