GtkCheckMenuItem::set_active
void set_active(bool is_active);
set_active() sets
the state of the calling GtkCheckMenuItem
to either the GTK_STATE_ACTIVE or the
GTK_STATE_NORMAL GtkStateType.
When the menu item is in its active state, the toggle indicator is
always displayed.
$checkmenuitem->set_active(true);
will set the GtkCheckMenuItem's state to
active.
The default setting is false.
