Some keyboard shortcuts impossible to set

On version 1.9.6.0 it seems to be impossible to set the keyboard shortcut; Ctrl+Shift+1

Actually pressing the keys results in the ‘key sequence’ box results in Ctrl+Shift+!

Also, pasting in the text from another editor doesn’t work as a workaround, even though pasting is possible via the context menu. The pasted text just doesn’t seem to get recognised.

Cheers,
David