The only place Load3 is ever called with bUseMask true is from

LoadFromNode.  The code path doesn't give any way of setting the
size, so it doesn't work.  Remove it, and use EnableMask.

stepmania/src/ScreenSelectMaster.cpp

@@ -135,7 +135,6 @@ void ScreenSelectMaster::Init()
 				SCROLLER_FAST_CATCHUP,
 				SCROLLER_TRANSFORM,
 				SCROLLER_SUBDIVISIONS,
-				false,
 				LOOP_SCROLLER );
 			m_Scroller[*p].SetName( "Scroller"+PLAYER_APPEND_NO_SPACE(*p) );
 			this->AddChild( &m_Scroller[*p] );