2011/12/6 Henning Thielemann <lemming@henning-thielemann.de>

I have a textCtrl 'editor' and a menu item 'editorVisible' that controls
the visibility of the textCtrl.

    set editorVisible
        [ on command := do
             b <- get editorVisible checked
             set editor [ visible := b ] ]

I had the same problem, and I couldn't solve it the way I wanted.
It's old but I think I read that I shouldn't use visible for this, but remove the element from the layout and re-set the modified layout.

David.