This is a Combo widget for Gtk+. It's a composite widget (an HBox) and it has an entry and a list. You can use it like an entry and to track changes you should connect to the "changed" signal of combo->entry. The list can contain anything, but you should supply a function if you want to use widgets other than GtkLabels to get a string out of your widgets (an example is provided for a two-column list). The value in the entry can be limited to those in the list using gtk_combo_set_flag(combo, GTK_COMBO_IN_LIST_VALUE). It would be useful to add completion support in the entry. I haven't found a way to set the size correctly for the popup window (it's incorrect for lists with few items). Have fun.