Bug 268533 [Viewers] Weird painting when using MOUSE_CLICK_ACTIVATION
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/SWTFocusCellManager.java
if (!tmp.equals(focusCell)) {
					setFocusCell(tmp);
				}
			}
		}
		if (navigationStrategy.shouldCancelEvent(viewer, event)) {
			event.doit = false;
		}
	}
	private void handleSelection(Event event) {
		if ((event.detail & SWT.CHECK) == 0 && focusCell != null && focusCell.getItem() != event.item
				&& event.item != null && ! event.item.isDisposed() ) {
			ViewerRow row = viewer.getViewerRowFromItem(event.item);
			Assert
					.isNotNull(row,
							"Internal Structure invalid. Row item has no row ViewerRow assigned"); 
			ViewerCell tmp = row.getCell(focusCell.getColumnIndex());
			if (!focusCell.equals(tmp)) {
				setFocusCell(tmp);
			}
		}
	}
	/**
	 * Handles the {@link SWT#FocusIn} event.
	 * 
	 * @param event the event
	 */
	private void handleFocusIn(Event event) {
		if (focusCell == null) {
			setFocusCell(getInitialFocusCell());