Ctrl+E (Execute) Not working?

In SQL 2012 Management Studio, my favourite shortcut for running scripts stopped working mysteriously, A message in the bar at the bottom read ...

 (Ctrl+E) was pressed. Waiting for second key of chord...

The reset instructions are shown below the screenshot.

The 'fix' for this, is 

1. Go to Tools > Options
2. Open the 'Environment' section of the tree and select 'Keyboard'
3. On the right you will see a 'Reset' button.
4. Click it and Keyboard shortcuts will be returned to their defaults.