Can't close document!

[Angus Leeming]

If I open a document (only 1) and then decide to close it, I can't.

I get a little message to the minibuffer saying I'm not allowed to do this 
and (worse) the File menu has reverted to the No Buffer variant so I can do 
nothing useful with the document that I'm not allowed to close.

This is crap (both counts). Please revert to the old behaviour.

Angus