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/ComboBoxCellEditor.java
*/
protected Control createControl(Composite parent) {
	
	comboBox = new CCombo(parent, SWT.NONE);
	comboBox.setFont(parent.getFont());
	comboBox.addKeyListener(new KeyAdapter() {
		  
		public void keyPressed(KeyEvent e) {
			keyReleaseOccured(e);
		}
	});
	comboBox.addSelectionListener(new SelectionAdapter() {
		public void widgetDefaultSelected(SelectionEvent event) {
			
			selection = comboBox.getSelectionIndex();
			Object newValue = doGetValue();
			boolean newValidState = isCorrect(newValue);
			if (newValidState) {
				doSetValue(newValue);
			} else {
				
				setErrorMessage(
					MessageFormat.format(getErrorMessage(), new Object[] {items[selection]})); 
			}
			fireApplyEditorValue();
		}
	});
	comboBox.addTraverseListener(new TraverseListener() {
		public void keyTraversed(TraverseEvent e) {
			if (e.detail == SWT.TRAVERSE_ESCAPE || e.detail == SWT.TRAVERSE_RETURN) {