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
e.doit = false;
			}
		}
	});
	return comboBox;
}
/**
 * The <code>ComboBoxCellEditor</code> implementation of
 * this <code>CellEditor</code> framework method returns
 * the zero-based index of the current selection.
 *
 * @return the zero-based index of the current selection wrapped
 *  as an <code>Integer</code>
 */
protected Object doGetValue() {
	return new Integer(selection);
}
/* (non-Javadoc)
 * Method declared on CellEditor.
 */
protected void doSetFocus() {
	comboBox.setFocus();
}
/**
 * The <code>ComboBoxCellEditor</code> implementation of
 * this <code>CellEditor</code> framework method sets the 
 * minimum width of the cell to 50 pixels to make sure the
 * arrow button and some text is visible. The list of CCombo
 * will be wide enough to show its longest item.
 */