Whats the right way to add gtk components to Emacs?

[joakim]

I the Xwidget branch I add gtk components to the buffer. It works mostly
well. Some cases dont work too well:

- If I create a new toplevel window and add a component to it, Emacs
  crashes.
- If I make an offscreen buffer and try to catch damage events, many
  events seemingly get lost.

Emacs does some kind of trickery with X events which I suspect is the
root cause. How does this work? How do I make my more complicated
components work in this scheme?   
-- 
Joakim Verona