+UndoTransaction::add_command (Command *const cmd)
+{
+ /* catch death of command (e.g. caused by death of object to
+ which it refers. command_death() is a normal static function
+ so there is no need to manage this connection.
+ */
+
+ cmd->DropReferences.connect_same_thread (*this, boost::bind (&command_death, this, cmd));
+ actions.push_back (cmd);
+}
+
+void
+UndoTransaction::remove_command (Command* const action)
+{
+ actions.remove (action);
+}
+
+bool
+UndoTransaction::empty () const