playing with the new 3.20 GTK packages (win32) from the GtkD website i
ran into 2 issues.

1) the theme is very different from 3.18 and does not fit in at all - it
rather looks like a Mac theme. it has very rounded corners and there is
no app icon in the upper left corner of the window. maybe this package
is lacking the windows theme altogether? maybe a small config entry/file
is missing?

2) as the GTK developers made the inexplicable decision to give Notebook
widgets (and their tabs) a hard-coded white background, instead of the
typical transparent/fall-through-to-system color, i am using following
fix for my programs:

enum myCSS = q{
     GtkNotebook {
         background-color: #e9e9e9;
     }
     GtkNotebook tab {
         background-color: #d6d6d6;
     }
};
...
int main(string[] args){
...
     import gtk.CssProvider;
     auto styleProvider = new CssProvider;
     styleProvider.loadFromData(myCSS);
     import gdk.Screen;
     import gtk.StyleContext;
     StyleContext.addProviderForScreen( Screen.getDefault(), 
styleProvider, 800);

(i then use the Builder to load my GUI from glade files.)

unfortunately, this fix does not work anymore with the 3.20 package, the
background stays white!

also, not sure how serious this is, i get a new warning that i have not
seen before:

GLib-GObject-WARNING **: attempt to override closure->va_marshal
(63c488b0) with new marshal (66925ea8)

thanks
/det