Activate the named action within action_group.
If the action is expecting a parameter, then the correct type of
parameter must be given as parameter. If the action is expecting no
parameters then parameter must be NULL. See
g_action_group_get_parameter_type().
Since 2.28
Activate the named action within action_group. If the action is expecting a parameter, then the correct type of parameter must be given as parameter. If the action is expecting no parameters then parameter must be NULL. See g_action_group_get_parameter_type(). Since 2.28