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
* Method declared on CellEditor.
 * The focus is set to the cell editor's button. 
 */
protected void doSetFocus() {
	button.setFocus();
}
/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected void doSetValue(Object value) {
	this.value = value;
	updateContents(value);
}
/**
 * Returns the default label widget created by <code>createContents</code>.
 *
 * @return the default label widget
 */
protected Label getDefaultLabel() {
	return defaultLabel;
}
/**
 * Opens a dialog box under the given parent control and returns the
 * dialog's value when it closes.
 * <p>
 * This framework method must be implemented by concrete subclasses.
 * It is called when the user has pressed the button and the dialog
 * box must pop up.
 * </p>
 *