Bug 181061 [Viewers] JFace viewers performance issues in 3.3
A number of the JFace performance tests are red since I20060926-0800.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewer.java
if (viewerEditor != null) {
			control.addMouseListener(new MouseAdapter() {
				public void mouseDown(MouseEvent e) {
					handleMouseDown(e);
				}
			});
		}
	}
	/**
	 * Creates the viewer editor used for editing cell contents. To be
	 * implemented by subclasses.
	 * 
	 * @return the editor, or <code>null</code> if this viewer does not
	 *         support editing cell contents.
	 */
	protected abstract ColumnViewerEditor createViewerEditor();
	/**
	 * Returns the viewer cell at the given widget-relative coordinates, or
	 * <code>null</code> if there is no cell at that location
	 * 
	 * @param point
	 *            the widget-relative coordinates
	 * @return the cell or <code>null</code> if no cell is found at the given
	 *         point
	 */
	ViewerCell getCell(Point point) {
		ViewerRow row = getViewerRow(point);