I am writing an app in which several views require full screen mode without control bar (CB).
I use the following code in the view's DoActivate() and other parts of the code:

I get the desired behaviour. However, whenever there is an event that requires CB, the CB is displayed and is left on after the event is over.
For example, if a dialog or note appears, they turn on the CB. The CB is left on after the dialog / note is dismissed.
Also, if the display goes off and back on, the CB appears.

What do I have to do to make sure that CB is always hidden when a view is displayed and, if anything makes CB appear, it is goes off again after that event (dialog, note, etc) is over?