[Development] QtQuick Dialogs Widgets fallback

[Kai Uwe Broulik]

Hi,
> Which style are you referring to here?

The default QML one, none Fusion/Material/etc substyles.

> If there's a way we can improve our desktop-based fallbacks, it would be good to know about that.

First of all, they suffer from the same issue as most of QtQuick 
Controls 2, being in the same scene, which is fine for embedded or 
mobile but not how desktops work.

It means the dialog doesn't have title bar, not the proper shadow around 
it, cannot be moved out of the way, cannot exceed the scene's bounds, etc.

More importantly, though, the dialog's size seems fixed to 320x160. If 
you add three buttons (Save Changes? Apply / Discard / Cancel), the 
DialogButtonBox already gets too wide on most locales.

They also cannot have an icon (error icon, exclamation mark, question 
mark), which you would expect from a message box.

Cheers
Kai Uwe