Bug 296822 NullProgressMonitor is not thread safe for expected usage
NullProgressMonitor.setCanceled and isCanceled access the cancelled field, but there's no synchronization. The expected use is that setCanceled is called from a thread other than the one doing the work, which polls isCanceled(), so this needs to be thread safe. Could either make these two methods synchronized or make the field volatile. Should check other progress monitor implementations too.
bundles/org.eclipse.jface/src/org/eclipse/jface/wizard/ProgressMonitorPart.java
import org.eclipse.jface.dialogs.ProgressIndicator;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.core.runtime.Assert;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Event;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Layout;
import org.eclipse.swt.widgets.Listener;
/**
 * A standard implementation of an IProgressMonitor. It consists
 * of a label displaying the task and subtask name, and a
 * progress indicator to show progress. In contrast to
 * <code>ProgressMonitorDialog</code> this class only implements
 * <code>IProgressMonitor</code>.
 */
public class ProgressMonitorPart extends Composite implements
        IProgressMonitorWithBlocking {
	
    protected Label fLabel;
    
    protected String fTaskName;
    
    protected String fSubTaskName;