I would like to open "submaps" (i.e. other mind maps using the file hyperlink) in the same tab as the parent.

Then I would like to go back and forth between them using my mouses back/forward buttons.
This would make my mind maps three dimensional in a way, and I could "zoom in".

If you get really creative, you could later on create a 3D viewer for this :) having 2D layers on top of each other plus linking vertical lines and some 3D navigation/flight control to let me "fly in the map".

ps. I would also like the CTRL+TAB and CTRL+SHIFT+TAB work for back/forward.