Well callBacks are used to update the control when scrubbing and is disabled when play is pressed but updates as soon as it has stopped playing. The controls when interacted with directly drive ca def parameters that they are associated with.
Did you see this?
The whole thing is setup using XML files that you can build as presets. Once setup the XML file is not needed as it is stored in the def that is created so that every thing except the UI is local to the file. When the UI is launched and the control panel picked from the scene list it reads in the XML and builds the UI making all the associations via the tab property of each control.
Very fast and simple to setup a UI, all you need to do is wire the morphs, bones, what ever to the parameters and away you go. The location of the controls in the UI is all automatic but you have the ability to force a new row and use offset values to get it just the way you want. Also the groups and their colours are what ever you want as well.
This is the latest test xml file format.