Bug 170668 [DataBinding] [Patch] Add SWTObservables.observeTooltipText()
Adds support for binding to SWT Control TooltipText property.
bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/databinding/swt/SWTObservables.java
private Display display;
		/**
		 * @param display
		 */
		private DisplayRealm(Display display) {
			this.display = display;
		}
		public boolean isCurrent() {
			return Display.getCurrent() == display;
		}
		public void asyncExec(Runnable runnable) {
			display.asyncExec(runnable);
		}