Uicontrol callbacks
This post details undocumented callbacks exposed by the underlying Java object of Matlab uicontrols, that can be used to modify the control's behavior in a multitude of different events
UIInspect
Button customization
Matlab's button uicontrols (pushbutton and togglebutton) are basically wrappers for a Java Swing JButton object. This post describes how the buttons can be customized using this Java object in ways