This is seriously one of the best submissions on File Exchange!
I've been browsing the code, and I can see that it's finally possible in R2014b to subclass MATLAB uicontrols (uix.Container in v2 inherits from matlab.ui.container.internal.UIContainer, instead of being a wrapper as in v1)!
However whenever I try this with my own classes, I get an error that "Class 'MyControl' is not an allowed subclass of class 'matlab.ui.container.internal.UIContainer'."... Are your classes hardcoded in MATLAB as allowed subclasses, but no one else??