What are GUI builder options for D?

[solidstate1991]

On Thursday, 28 May 2020 at 19:38:25 UTC, Jack J. wrote:
> drag-and-drop GUI builder, similar to Qt/visual studio (C#'s 
> GUI designer). What are the options for D?

I have created one for my game engine's own GUI framework. It's 
called WindowMaker for PPE/Concrete. However - unless you want 
your app to look like it's out from the 90's - you might not want 
to use it for modern apps.