Expert Answer:
s:
You need to access the underlying Java Swing component (I am using FINDJOBJ function):
figure('Menubar','none', 'Position',[200 200 300 200]) h = uicontrol('Style','pushbutton', 'String','click', ... 'Units','normalized', 'Position',[0.3 0.3 0.5 0.5]); jh = findjobj(h); jh.setVerticalAlignment( javax.swing.AbstractButton.BOTTOM );