What class to use to layout widgets within themselves?

Question

Qt

I need to make nesting like in the picture.
For 3, I use QGridLayout, just add some widgets (SpinBox) without problems, but nesting is needed.

Which is better to use for containers 1 and 2?
In 1, I will just have spinboxes vertically, I tried to add another QGridLayout to QGridLayout, but it stupidly stretches, QMdiArea is simply not displayed after adding.

Answer 1

Use VerticalLayout and HorizontalLayout in the combinations you need.