childFrame->GetNextSibling(&childFrame);
childFrame = childFrame->GetNextSibling();
PRInt32 nsTableFrame::GetSpecifiedColumnCount (){  PRInt32 colCount = 0;  nsIFrame * childFrame = mColGroups.FirstChild();  while (nsnull!=childFrame) {    colCount += ((nsTableColGroupFrame *)childFrame)->GetColCount();    childFrame->GetNextSibling(&childFrame);  }      return colCount;}