Bug 29163 SafeRunnable needs to be accessible in JFace
We need to be able to access the SafeRunnable in JFace in order that some error protection can be added to preferences and properties dialogs.
bundles/org.eclipse.ui.workbench/extensions/org/eclipse/jface/operation/ModalContext.java
private IRunnableWithProgress runnable;
		
		/** 
		 * The exception thrown by the operation starter.
		 */
		private Throwable throwable;
		
		/**
		 * The progress monitor used for progress and cancelation.
		 */
		private IProgressMonitor progressMonitor;
		
		/**
		 * The display used for event dispatching.
		 */
		private Display display;
		
		/**
		 * Indicates whether to continue event queue dispatching.
		 */
		private volatile boolean continueEventDispatching = true;
		/**
		 * Creates a new modal context.
		 * 
		 * @param operation the runnable to run
		 * @param monitor the progress monitor to use to display progress and receive
		 *   requests for cancelation
		 * @param display the display to be used to read and dispatch events
		 */
		private ModalContextThread(IRunnableWithProgress operation, IProgressMonitor monitor, Display display) {