I had the same problem and found the answer here (For some reason the ButtonDownFcn just doesn't work and is simply useless for the uitable):
And then you can register additional callbacks using the underlying Java object.
jscrollpane = findjobj(htable);
jviewport = jscrollpane.getViewport;
jtable = jviewport.getView;
set(jtable, 'MouseClickedCallback', @onClick);
Where onClick() is a regular matlab function that takes two arguments (handle and eventdata). There are other callbacks you can register as well, like
MouseWheelMovedCallback
MouseClickedCallback
MouseEnteredCallback
MouseExitedCallback
MousePressedCallback
MouseReleasedCallback
... and those are just the ones related to mouse events. Use get(jtable) to find out what else is available.
This works for me in version R2013a.
