PROTECTED constructor is needed to subclass SynthTabbedPaneUI

-------------------------------------------------------------
CR#6912118 :
I'm also going to make SynthTabbedPaneUI constructor protected. It is now private, which makes no sense.
*** (#2 of 2): 2010-01-22 21:22:16 MSK ###@###.###

CR#6978052
A private constructor was removed from SynthTabbedPaneUI as part of 6912118, so now a default public ctor is generated. I'm going to restore the private one.
*** (#1 of 1): 2010-09-17 21:33:46 MSD ###@###.###