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
* @param parent the parent control
 * @param style the style bits
 * @since 2.1
 */
protected DialogCellEditor(Composite parent, int style) {
	super(parent, style);
}
/**
 * Creates the button for this cell editor under the given parent control.
 * <p>
 * The default implementation of this framework method creates the button 
 * display on the right hand side of the dialog cell editor. Subclasses
 * may extend or reimplement.
 * </p>
 *
 * @param parent the parent control
 * @return the new button control
 */
protected Button createButton(Composite parent) {
	Button result = new Button(parent, SWT.DOWN);
	result.setText("..."); 
	return result;
}
/**
 * Creates the controls used to show the value of this cell editor.
 * <p>
 * The default implementation of this framework method creates
 * a label widget, using the same font and background color as the parent control.
 * </p>
 * <p>