Snipping Tool Ctrl + Print Screen Hotkey Doesn't Work

I was having trouble capturing right-click context menus.  With the snipping tool included in Windows 8.1 (although this would like be a problem in Windows 7 too).  I tried uninstalling Dropbox since it tries to use the Prt-Srn button as a hotkey for screen captures too.  That didn't fix it.

The Actual Solution

Turns out my KVM was interfering because it uses the Ctrl key for switching.  Plugged a keyboard directly into my machine and now I can open the Snipping Tool, right click to bring up a context menu in another application, press Ctrl + Prt-Scrn and a screen capture is triggered.

It took far too long to figure this out.  I was sure it was a software problem.

Hope this helps!