Displays the contents of a cell in a GtkTreeView as a GtkComboBox.
-- Creates a new GtkCellRendererCombo.
Use get_property and set_property methods to access these.
has-entry: If FALSE, don't allow entering strings other than the given ones (from the model). model: The tree model containing the possible values for the combo box entry. text-column: The column number in the data model that will be used to get the strings from.