For some columns I want to display additional information in the header and the information should be printed over the column borders. To archive this I extended the theme with following snippet:
VerticalTextPainter firstPainter = new VerticalTextPainter(false, true, true, false);
TextPainter secondPainter = new TextPainter(); // TextPainter as a demonstrator for this question
CellPainterDecorator painterDecorator = new CellPainterDecorator(firstPainter, CellEdgeEnum.TOP, secondPainter);
At the moment I'm avoiding the grouping feature, because of performance problems. Is it possible to paint over cell boundaries? Or has anyone another idea how to approach this?