Hi Stefan,
not everything is a bug

Something was designed to be like it behaves.
For example when you swtich views, from Web Browser to Text editor, I hide browser toolbar and show editor toolbar automatically. And vice versa. Because normally you do not need them both.
Now the question: what to do with this smartness, if user has closed the toolbat manually? Or called
None? Shell I disable automatic showing of the toolbar next time?
So, somehow I also need to distingush, is hiding of the toolbar was
automatic or manual done by user.
With hiding of
main menu... it is very difficult to do such "defence" everywhere... What I can design is only some shortcut to toggle only main menu. Because all other methods would require a lot of time for some artifical case...