Bug 313297 XML data set fail in chart data preview
chart/org.eclipse.birt.chart.ui/src/org/eclipse/birt/chart/ui/swt/CustomPreviewTable.java
}
		int defaultWidth = iWidth - SPLITTER_WIDTH;
		int preferWidth = btnHeader.computeSize( SWT.DEFAULT, SWT.DEFAULT ).x;
		if ( preferWidth > defaultWidth )
		{
			fd.width = preferWidth;
			columnWidths.remove( index );
			columnWidths.add( index, Integer.valueOf( preferWidth + SPLITTER_WIDTH ) );
		}
		else
		{
			fd.width = defaultWidth;
		}
		
		int h = ChartUIUtil.getImageButtonDefaultHeightByPlatform( );
		if ( h > 0 )
		{
			fd.height = h;
		}
		btnHeader.setLayoutData( fd );
		btnHeader.setVisible( true );
		btnHeader.addListener( SWT.Selection, headerButtonListener );
		btnHeader.addKeyListener( this );
		btnHeader.addTraverseListener( traverseListener );
		btnHeader.addListener( SWT.FocusIn, headerButtonListener );
		btnHeader.addMouseListener( this );
		btnHeader.addMouseMoveListener( this );
		
		addDragListenerToHeaderButton( btnHeader );
		btnHeaders.add( btnHeader );