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
package org.eclipse.jface.viewers;
/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import org.eclipse.jface.util.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CCombo;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.widgets.*;
import java.text.MessageFormat;
/**
 * A cell editor that presents a list of items in a combo box.
 * The cell editor's value is the zero-based index of the selected
 * item.
 * <p>
 * This class may be instantiated; it is not intended to be subclassed.
 * </p>
 */
public class ComboBoxCellEditor extends CellEditor {
	/**