How to add minimize button to GTKDialog?

Hi,
I found that on some platforms like Ubuntu 20.04 or Windows 10 minimize button is missing on Dialog

But other users say that e.g. on Plasma Desktop there are.

How can I enable it on all platforms?

Every Window Manager decorates dialogs the way it wants to: some add the minimize button to the decoration, others don’t.

Does your application consist of that dialog alone, or is that dialog a transient of another window?