Bug 174701 [Viewers] ViewerRow should be reused instead of connected to the Item
Currently we create a ViewerRow ver every Item we create this can degrade performance, we should cache the row and reuse it
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ColumnViewerEditor.java
*     IBM Corporation - initial API and implementation
 *     Tom Schindl <tom.schindl@bestsolution.at> - refactoring (bug 153993)
 *     											   fix in bug 151295
 *                                                 fix in bug 166500
 ******************************************************************************/
package org.eclipse.jface.viewers;
import org.eclipse.core.runtime.ListenerList;
import org.eclipse.swt.SWT;
import org.eclipse.swt.events.FocusAdapter;
import org.eclipse.swt.events.FocusEvent;
import org.eclipse.swt.events.FocusListener;
import org.eclipse.swt.events.MouseAdapter;
import org.eclipse.swt.events.MouseEvent;
import org.eclipse.swt.events.MouseListener;
import org.eclipse.swt.events.TraverseEvent;
import org.eclipse.swt.events.TraverseListener;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Item;
/**
 * This is the base for all editor implementations of Viewers. ColumnViewer
 * implementators have to subclass this viewer and implement the missing methods
 * 
 * @since 3.3 <strong>EXPERIMENTAL</strong> This class or interface has been
 *        added as part of a work in progress. This API may change at any given
 *        time. Please do not use this API without consulting with the
 *        Platform/UI team.
 * 
 */
public abstract class ColumnViewerEditor {