My son finished the story mode and he is now playing around with the creative mode.
However it seems there is some kind of bug woth the middle mouse button. When he is using the middle mouse button, the menu is supposed to show up so that he can exit/save/use power ups or whatever.
In his case sometimes it does work as it should, but most of the time the menu would not appear at all (displaying only the “creative mode” message on the top screen). Sometimes the menu appear on the back overlayed by the Minecraft pi welcome menu. Only way to fix is to restart, which is frustrating when you spent time building stuff.
Thanks for any advices!