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
public LayoutData getLayoutData() {
	LayoutData layoutData = super.getLayoutData();
	layoutData.minimumWidth = 50;
	return layoutData;
}
/**
 * The <code>ComboBoxCellEditor</code> implementation of
 * this <code>CellEditor</code> framework method
 * accepts a zero-based index of a selection.
 *
 * @param value the zero-based index of the selection wrapped
 *   as an <code>Integer</code>
 */
protected void doSetValue(Object value) {
	Assert.isTrue(comboBox != null && (value instanceof Integer));
	selection = ((Integer) value).intValue();
	comboBox.select(selection);
}
/**
 * Add the items to the combo box.
 */
private void populateComboBoxItems() {
	if (comboBox != null && items != null) {
		for (int i = 0; i < items.length; i++)
			comboBox.add(items[i], i);
		setValueValid(true);
	}
}
}