Bug 12329 [Cell Editors] Request:ComboBoxCellEditor READ_ONLY style
Although CCombo accepts SWT.READ_ONLY style, there is no way to specify style when it is used in ComboBoxCellEditor. How about adding createControl(Composite parent, int style) method to ComboBoxCellEditor class?
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/CellEditor.java
* Property name for the find action
	 */
	public static final String FIND = "find"; 
	/**
	 * Property name for the paste action
	 */
	public static final String PASTE = "paste"; 
	/**
	 * Property name for the redo action
	 */
	public static final String REDO = "redo"; 
	/**
	 * Property name for the select all action
	 */
	public static final String SELECT_ALL = "selectall"; 
	/**
	 * Property name for the undo action
	 */
	public static final String UNDO = "undo"; 
/**
 * Creates a new cell editor under the given parent control.
 * The cell editor has no cell validator.
 *
 * @param parent the parent control
 */
protected CellEditor(Composite parent) {
	control = createControl(parent);