Safari is crashing when I move tabs

For some reason, whenever I drag around tabs (such as dragging a single tab window into a two tab window to make a three tab window), Safari quits. I'm not sure why this is. It could be because I recently downloaded a few Safari add-ons, specifically these ones:

Safari Add-ons

but I got rid of all of them and I still have the problem. I also restarted the computer.

Safari Menu > Reset Safari...

No luck with that? Then try replacing the plist file for Safari.

Still no good? Try logging in under a different user account.

I tried resetting under the menu first and then reset through preferences (by removing all add-ons). Preferences seemed to work.

Thanks for your help.