Modifing the right mouse menu in a GtkEntry possible?

["Mart van Wijngaarden" <softwaredev conftech nl>]

Hi,

I've a question about the popup menu which appear when you click with your
right mouse button in a GtkEntry.

I want to give the user the possibility to select  a default text from a
list and put this into an Entry by simple clicking with the right mouse
button or just typing his own text.

When you click right, the default menu (with copy, cut, paste etc)
appears. Is it possible to modify this menu (so add some extra lines)? Or
should I disable this menu (Is this possible?) and create a new one?

Mart