Giving focus to a window

[Anders Melchiorsen <and kampsax dtu dk>]

This so simple that it is a bit embarrassing to ask, but I was unable
to find information on this and any activate/focus sounding functions
I used did not work.

How do I make the window manager give focus to one of my GtkWindow's?
I want to pop to front and activate my main window when a child window 
is closed. The popping to front now works but it does not get focus.
-- 
Mvh. Anders