CellRenderer.addOnEditingStarted

This signal gets emitted when a cell starts to be edited. The intended use of this signal is to do special setup on editable, e.g. adding a gtk.EntryCompletion or setting up additional columns in a gtk.ComboBox

See gtk_cell_editable_start_editing() for information on the lifecycle of the editable and a way to do setup that doesn’t depend on the renderer.

Note that GTK+ doesn't guarantee that cell renderers will continue to use the same kind of widget for editing in future releases, therefore you should check the type of editable before doing any specific setup, as in the following example:

static void
text_editing_started (GtkCellRenderer *cell,
GtkCellEditable *editable,
const gchar     *path,
gpointer         data)
{
if (GTK_IS_ENTRY (editable))
{
GtkEntry *entry = GTK_ENTRY (editable);

// ... create a GtkEntryCompletion

gtk_entry_set_completion (entry, completion);
}
}