Bug 61713 MessageDialog can't be created in non UI thread anymore
I20040511 In the past it was possible to create a MessageDialog from non UI threads. This is not possible with I20040511 anymore. Doing so now results in an invalid thread access to due the fact that the images are now managed by SWT.
bundles/org.eclipse.jface/src/org/eclipse/jface/resource/ImageRegistry.java
* 	   Steven Ketcham (sketcham@dsicdi.com) - Bug 42451
 * 			[Dialogs] ImageRegistry throws null pointer exception in 
 * 			application with multiple Display's
 *******************************************************************************/
package org.eclipse.jface.resource;
import java.util.*;
import org.eclipse.jface.dialogs.Dialog;
import org.eclipse.jface.util.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.widgets.Display;
/**
 * An image registry maintains a mapping between symbolic image names 
 * and SWT image objects or special image descriptor objects which
 * defer the creation of SWT image objects until they are needed.
 * <p>
 * An image registry owns all of the image objects registered
 * with it, and automatically disposes of them when the SWT Display
 * that creates the images is disposed. Because of this, clients do not 
 * need to (indeed, must not attempt to) dispose of these images themselves.
 * </p>
 * <p>
 * Clients may instantiate this class (it was not designed to be subclassed).
 * </p>
 * <p>
 * Unlike the FontRegistry, it is an error to replace images. As a result
 * there are no events that fire when values are changed in the registry
 * </p>
 */
public class ImageRegistry {