public void centerHorizontally(int top) {

        if (Position.FIXED.getCssName().equals(getElement().getStyle().getPosition())) {
            show();
            // keep position fixed, as may have been set to absolute
            setPositionFixed();
            int left = (Window.getClientWidth() - getOffsetWidth()) >> 1;
            setPopupPosition(Math.max(left, 0), Math.max(top, 0));
        } else {
            show();
            int left = (Window.getClientWidth() - getOffsetWidth()) >> 1;
            setPopupPosition(Math.max(Window.getScrollLeft() + left, 0), Math.max(Window.getScrollTop() + top, 0));
        }
    }
public void centerHorizontally ( int top ) { if ( Position . FIXED . getCssName ( ) . equals ( getElement ( ) . getStyle ( ) . getPosition ( ) ) ) { show ( ) ; setPositionFixed ( ) ; int left = ( Window . getClientWidth ( ) - getOffsetWidth ( ) ) > > 1 ; setPopupPosition ( Math . max ( left , 0 ) , Math . max ( top , 0 ) ) ; } else { show ( ) ; int left = ( Window . getClientWidth ( ) - getOffsetWidth ( ) ) > > 1 ; setPopupPosition ( Math . max ( Window . getScrollLeft ( ) + left , 0 ) , Math . max ( Window . getScrollTop ( ) + top , 0 ) ) ; } }
Shows the dialog and centers it horizontally, but positions it at a fixed vertical position.<p>

@param top the top position