You can set Hotkeys for simple tasks such as Force Screen Capture or Pause/Stop Session in Web Explorer Settings.
Click the Configuration icon from top left corner of Web Explorer Dialog to access the list of Hotkeys settings.
Select keys for the combination as appropriated.
A Capturable Web Tab means a Web Tab that can be captured by Web Explorer. Currently, there are certain special site that could not be recognize such as the default blank page or Chrome Store Site. This would occurs in Chrome and Safari. Firefox does not have this limitation yet.
In Chrome, you can specify global shortcuts that work on all tabs. The total number of shortcuts is limited though