Two level navigation - only on certain page

Spend our of try with vision to make a simple “two stage” navigation. Everything i try broke the interface.

I want a simple docked windows that is used as a navigation with a tab strip and under it that main window with a content, it’s easy, it’s working great.

I one of the page reachable by this tab strip (represented yellowish) i want to call another docked windows that could call multiple other windows using a tab strip (represented in green)

The project is setup as “north/south” in his propreties, if one of the main windows is setup as something else than floating they “pile up” one under the other, if a set everything as float, the second level docker windows just dissapear when entering the subpage, etc.

Tried a lot of things, it end up not working of breaking up the interface.

Has someone a simple advice on how to do that ?

A constant 2-tier nav is relatively easy. A conditional 3rd tier I typically just use a multistate pushbutton on the view to swap between however many templates you need in the 3rd tier.