That's explained in the 1st line of the post:<p>"If you are fond of double-clicking the Title bar of a window to minimize"<p>If you are <i>not</i> fond of double-clicking the title bar, then you probably weren't looking for the UI change from Lion to Mountain Lion.
Very unfortunate title imho, since minimising windows can be accomplished by far easier methods (the button in the menu or pressing command+M for instance).