Bug 255229 [Viewers] [3.5] NPE in ColumnViewerToolTipSupport
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ViewerRow.java
*     IBM Corporation - initial API and implementation
 *     Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
 *                                               - fix in bug: 166346,167325,174355,195908,198035,215069,227421
 *******************************************************************************/
package org.eclipse.jface.viewers;
import org.eclipse.jface.util.Policy;
import org.eclipse.swt.custom.StyleRange;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Widget;
/**
 * ViewerRow is the abstract superclass of the part that represents items in a
 * Table or Tree. Implementors of {@link ColumnViewer} have to provide a
 * concrete implementation for the underlying widget
 * 
 * @since 3.3
 * 
 */
public abstract class ViewerRow implements Cloneable {
	/**
	 * Constant denoting the row above the current one (value is 1).
	 * 
	 * @see #getNeighbor(int, boolean)
	 */
	public static final int ABOVE = 1;
	/**