Visual Studio for Mac's shell code is written in gtk+ 2. We have supporting code in gtk+ to allow mixing gtk widgets with native widgets.

But the glue code isn't used here, because there is another interesting mechanism at play. The root window created by gtk on macOS is actually an NSWindow (see GdkQuartzWindow), thus you can use Cocoa APIs on the window. We just set the title visibility to hidden and set the native titlebar widget.

Nice! Thanks for the explanation.

Do you plan to port to GTK 3 in the future? Does version 2 even have HiDPI support?

The opinion of the GTK devs seems to be that it's very much the "gnome toolkit" and that cross platform is not planned at all.

That's not the opinion of everyone. Gedit for example has an up to date Windows version. Inkscape and GIMP both have macOS and Windows versions, but I think they still run version 2.

GNOME definitely is the focus as their resources are quite limited. That's why I welcome Microsoft using it and hope to see some improvements for Windows and macOS in the future.

Last time I tried it didn't even work well with cygwin, every app would take a minute to start up while it tried to talk to systemd.

You shouldn't use cygwin, but MSYS2: http://www.msys2.org/

For Gedit you can just download it here: https://wiki.gnome.org/Apps/Gedit It starts up immediately for me.

Inkscape and GIMP also have dedicated installers.

We have some glue code to workaround lack of retina/hidpi support in gtk+.

Yes, having Gtk UI running on Gtk 3 is something we want to have at some point.

This is the most unbelievable thing. Even WSL was kinda okay to imagine. But Microsoft and Gtk?

I thought after buying Xamarin they would replace Gtk part.

Unbelievable :D

Awesome! Thank you for still keeping up with GTK+ and hopefully also improving its support on macOS and Windows along the way.

> lack of retina/hidpi support in gtk+.

You should phrase this as "support in gtk+ 2", because since version 3 GTK+ supports HiDPI :)