Convenience function which constructs a new editable text combo box, which is a
ComboBoxEntry just displaying strings. If you use this function to create a text
combo box, you should only manipulate its data source with the following convenience functions:
append_text,
insert_text, prepend_text and
remove_text.
Creates a new ComboBoxEntry which has a
Entry as child and a list of strings as popup. You can get the
Entry from a ComboBoxEntry using
GTK_ENTRY (GTK_BIN (combo_box_entry)->child). To add and remove strings from the list, just modify model using its
data manipulation API.
