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
private void addHeaderButton( int style, String sColumnHeading, int iWidth )
	{
		Button btnHeader = new Button( cmpHeaders, style );
		FormData fd = new FormData( );
		fd.top = new FormAttachment( 2 );
		int i = btnHeaders.size( );
		if ( i == 0 )
		{
			fd.left = new FormAttachment( 0 );
		}
		else
		{
			Button btnNeighbor = btnHeaders.get( i - 1 );
			fd.left = new FormAttachment( btnNeighbor, SPLITTER_WIDTH );
		}
		fd.width = iWidth - SPLITTER_WIDTH;
		
		btnHeader.setLayoutData( fd );
		btnHeader.setText( sColumnHeading );
		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 );