When working with sub-controllers, getting the exact behavior specified is extremely important. In this case, we are going to make some very important decisions about the controls involved and how they interact. For our sub-controller, we are going to want the following:

• there will be some number of CAnimKnob objects to link together; we'll allow that number to vary depending on the application
• we will specifically use a single CTextButton object as the sole linking device; it will be labeled LINK
• when the LINK button is not depressed, the knobs will work independently
• when the LINK button is depressed, all knobs in the sub-controller's list will move together
• any other GUI control that shares the same control ID (tag) as the knobs will also update (see the original figure - the text edit controls also update as well)

Notice that we are relying on there being one CTextButton - you can certainly change that part of the paradigm. Sub-controllers are highly flexible! But for our design we will be using that bit of information in the coding.