Layout which I can put in front of another

[anda_skoa]

What you want is a widget that is not part of the layout.

Needs manual adjustment of height when its parent changes height, but that can easily be done using an event filter.

Cheers,
_

[adutzu89]

What you want is a widget that is not part of the layout.

Needs manual adjustment of height when its parent changes height, but that can easily be done using an event filter.

Cheers,
_

+ what anda_skoa said with adding: create a frameless widget(using window flags to remove your window frame) and add/show it whenever you need.
For the bottom and central widgets, why not add them in a QGridLayout?

I can't hide Left Widget (BorderLayout widgets don't have hide() option so I would have to hide every containing widget one by one)

If I am understanding this correctly you are saying that you add the widgets from inside left and bottom directly into the borderlayout, and not creating left/bottom widget and after that add other widgets to them?