Whenever my computer (iMac Intel core i3) goes to sleep, after it wakes up Firefox 4 freezes. I disabled all plug-ins/add-ons to see what was causing the problem. After enabling them one by one, I discovered that the diggo toolbar is the only add-on that causes this problem. When it freezes I'm unable to click a tab or hyperlink. It seems to disable my mouse as well (right clicking doesn't work either). I have to force quit in order to use the browser normally. I didn't have this problem with Firefox 3. I really love diigo, so I hope this is a known issue and someone has a solution,
Can you please uninstall the extension and reinstall it again to test whether the problem persists?