So, I see this is an issue with many people, but it also seems like trashing the preferences files (Defaults and SavedData) fixes the issue for most. Unfortunately, I'm not one of those people.
I'm running CS6 on Mac OS X 10.10.3. This just started happening; I was able to drag with the mouse just fine until the last few days. This spans over many app restarts as well as computer restarts. I trashed the preferences both manually, and with the ctrl+cmd+option+shift shortcut, with no change.
Please help. This is making my job nearly impossible to do right now. Thank you.