Visual Studio Keyboard Shortcut of quick watch (shift + F9) Not Working

If you have Snag-It installed on your machine, its global shortcuts may override application specific shortcuts in Visual Studio (or other apps).

See @nuri's answer here: Visual Studio 2010 QuickWatch window not visible for instructions and screen-shots to change the Snag-It settings.

In the meantime, just go into the Snag-It preferences, the HotKeys tab, and set the "Video capture start/pause/resume" hot key to something other than [Shift]-[F9]. For myself, I only use "Global capture", so I set everything else to "None".