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/TextCellEditor.java
if ((getControl() == null) || getControl().isDisposed())
				return;
			checkSelection(); 
			checkDeleteable();
			checkSelectable();
		}
	});
	text.addTraverseListener(new TraverseListener() {
		public void keyTraversed(TraverseEvent e) {
			if (e.detail == SWT.TRAVERSE_ESCAPE || e.detail == SWT.TRAVERSE_RETURN) {
				e.doit = false;
			}
		}
	});
	
	
	
	text.addMouseListener(new MouseAdapter() {
		public void mouseUp(MouseEvent e) {
			checkSelection();
			checkDeleteable();
			checkSelectable();
		}
	});
	text.setFont(parent.getFont());
	text.setBackground(parent.getBackground());
	text.setText("");
	text.addModifyListener(getModifyListener());
	return text;
}