Focus stealing is when a window unexpectedly acquires focus. You’re describing something different, a window not relinquishing focus because of a chosen and consistent (not universally appreciated, but justifiable) behaviour for modals.

Not a modal dialog. A right click menu.

I have had so many focus issues on gnome that what I meant is that they should do a new take on the whole thing. The problem has gotten worse, not better, over the years.

I understood that.

It’s fairly normal to treat context menus as modals within their parent window. Not universal, but my feeling (which I don’t trust here) is that it has been generally preferred for quite some time. I think this has also become a stronger custom as popovers have become more common, and pure context menus have become less common. It then makes sense to formalise on that pattern. And then applying the modal-closing behaviour across all windows makes sense, even if it’s not the only reasonable option and you’d prefer not.