All of that was already implemented by the toolkit. The way programs used to do it is by simply calling those 3-4 toolkit functions to move and resize. You can

All of that was already implemented by the toolkit. The way programs used to do it is by simply calling those 3-4 toolkit functions to move and resize. You can verify this by looking in the code to old versions of Audacious/XMMS/Beep/etc, which still used GTK/GDK to handle those things. I can't stress this enough: this kind of thing was already supported for quite a long time and app developers were doing it long ago. The only thing GTK3 added was a common look and feel for it. Qt also has that now too.