535814cf98
That list is used to set the automation state of all automatable controls when the global automation state is changed with the buttons at the top of the generic UI window. The controls were added to the list regardless of the automatable status, and some controls were even added multiple times: once in build_control_ui() and once in build(). Since changing the state of non-automatable controls is wrong, only add the control UI in build_control_ui() which already has the knowledge of automatable or not.
Please see the Ardour web site at http://ardour.org/ for all documentation..
For information on building ardour:
http://ardour.org/development.html