Bug 38247 [Viewers] [Javadoc] Incomplete javadoc for DialogCellEditor
The javadoc for #openDialogBox() does not say how to indicate that the dialog box was canceled. The de-facto behaviour is that if null is returned, it is considered as "cancel".
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/DialogCellEditor.java
*	<li><code>createButton</code>: creates the cell editor's button control</li>
 *	<li><code>openDialogBox</code>: opens the dialog box when the end user presses
 *      the button</li>
 *	<li><code>updateLabel</code>: updates the cell editor's label after its
 *		value has changed</li>
 * </ul>
 * </p>
 */
public abstract class DialogCellEditor extends CellEditor {
	/**
	 * Image registry key for three dot image (value <code>"cell_editor_dots_button_image"</code>).
	 */
	public static final String CELL_EDITOR_IMG_DOTS_BUTTON = "cell_editor_dots_button_image";
	/**
	 * The editor control.
	 */
	private Composite editor;
	/**
	 * The current contents.
	 */
	private Control contents;
	/**
	 * The label that gets reused by <code>updateLabel</code>.
	 */
	private Label defaultLabel;
	/**
	 * The button.
	 */
	private Button button;
	/**