mLastDir = vis->mDirection;
nsGfxScrollFrameInner::AddHorizontalScrollbar(nsBoxLayoutState& aState, nsRect& aScrollAreaSize, PRBool aOnTop){  if (!mHScrollbarBox)    return PR_TRUE;#ifdef IBMBIDI  PRInt32 dir = GetIntegerAttribute(mHScrollbarBox, nsXULAtoms::dir, -1);  const nsStyleVisibility* vis = mOuter->GetStyleVisibility();  // when creating the scrollbar for the first time, or whenever   // display direction is changed, scroll the view horizontally  if (dir != vis->mDirection) {    SetAttribute(mHScrollbarBox, nsXULAtoms::curpos,                 (NS_STYLE_DIRECTION_LTR == vis->mDirection) ? 0 : 0x7FFFFFFF);    SetAttribute(mHScrollbarBox, nsXULAtoms::dir, vis->mDirection * mOnePixel);  }#endif // IBMBIDI    return AddRemoveScrollbar(aState, aScrollAreaSize, aOnTop, PR_TRUE, PR_TRUE);}