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
*/
public ICellEditorValidator getValidator() {
	return validator;
}
/**
 * Returns this cell editor's value provided that it has a valid one.
 *
 * @return the value of this cell editor, or <code>null</code>
 *   if the cell editor does not contain a valid value
 */
public final Object getValue() {
	if (!valid)
		return null;
	return doGetValue();
}
/**
 * Returns whether this cell editor is activated.
 *
 * @return <code>true</code> if this cell editor's control is
 *   currently visible, and <code>false</code> if not visible
 */
public boolean isActivated() {
	return control != null && control.isVisible();
}
/**
 * Returns <code>true</code> if this cell editor is
 * able to perform the copy action.
 * <p>
 * This default implementation always returns 
 * <code>false</code>.