embedding widgets

[Tomas Carnecky <tom dbservice com>]

I have created a modification to transmission that changes the look:

http://dbservice.com/ftpdir/tom/screenshot19.png

each line is one custom widget, with a few pango text layouts and the
progressbar in the background. That was quite easy, but how would I go
about embedding for example a whole GtkButton in my custom widget
without having to create a box? Is it somehow possible to access the
GtkButton render() and get_size() functions and use those?

thanks
tom