gtk_combo_box_[sg]et_active not orthogonal

[Diego Zuccato <diego otello alma unibo it>]

Hello all.

I just noticed that set/get active aren't orthogonal: if there's nothing
selected, get_active() returns -1, BUT I cant set_active(-1)... Actually
the only way I could find to "delete" selection is get_model,
set_model(NULL), set_model(oldmodel)... quite ugly, IMHO.

BTW, a signal that tracks popups could be really useful :-)

BYtE,
 Diego.