painter._invalidateLineRange(index, document.getDefaultRootElement() .getElementCount());
painter._invalidateLineRange(index,Math.max(getLineCount(), firstLine + visibleLines));
	protected void documentChanged(DocumentEvent evt)	{		DocumentEvent.ElementChange ch = evt.getChange(			document.getDefaultRootElement());		int count;		if(ch == null)			count = 0;		else			count = ch.getChildrenAdded().length -				ch.getChildrenRemoved().length;		if(count == 0)		{			int line = getLineOfOffset(evt.getOffset());			painter._invalidateLine(line);		}		else		{			int index = ch.getIndex();			painter._invalidateLineRange(index,				document.getDefaultRootElement()				.getElementCount());			updateScrollBars();		}	}