Thank you for the reply.
The sample you show does not remove the background image.
Obviously, I cannot see the code that makes this possible - if indeed there is any extra code to make this work.
If there is code, could you let me see it please?
I am evaluating version 5.3 to find out if it can be adapted to suit our needs before we buy.
So far it's mostly ok, but still having problems with dropdowns in the toolbar and this problem with the background image and losing the toolbar with some pages being edited in full screen mode.