What is the main use of "Widget" component (on Containers) on QT Designer?

Hi out there!

What is the main use of "Widget" component (on Containers) on QT Designer?

Can I use that to put an opengl widget over it?

Thanks a lot.

Well, the main use is probably that you can promote it to your own class, which is QWidget based.

Or you could fill this widget with other widgets at runtime. The widget you "design" is just a place holder.