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
private boolean isSelectable = false;
/**
 * Creates a new text string cell editor parented under the given control.
 * The cell editor value is the string itself, which is initially the empty string. 
 * Initially, the cell editor has no cell validator.
 *
 * @param parent the parent control
 */
public TextCellEditor(Composite parent) {
	super(parent);
}
/**
 * Checks to see if the "deleteable" state (can delete/
 * nothing to delete) has changed and if so fire an
 * enablement changed notification.
 */
private void checkDeleteable() {
	boolean oldIsDeleteable = isDeleteable;
	isDeleteable = isDeleteEnabled();
	if (oldIsDeleteable != isDeleteable) {
		fireEnablementChanged(DELETE);
	}
}
/**
 * Checks to see if the "selectable" state (can select)
 * has changed and if so fire an enablement changed notification.
 */
private void checkSelectable() {
	boolean oldIsSelectable = isSelectable;
	isSelectable = isSelectAllEnabled();