Bug 159600 [Viewers] Tooltips not working on TreeViewer
TooltipSupport does not map receiver-relative coordinates to display-relative coordinates => TreeViewer#getItem(int x, int y) returns wrong item.
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/ToolTipSupport.java
/* (non-Javadoc)
		 * @see org.eclipse.swt.widgets.Listener#handleEvent(org.eclipse.swt.widgets.Event)
		 */
		public void handleEvent(Event event) {
			CLabel label = (CLabel) event.widget;
			Shell shell = label.getShell();
			switch (event.type) {
			case SWT.MouseDown:
				viewer.setSelection(new StructuredSelection());
				
			case SWT.MouseExit:
				viewer.getControl().setFocus();
				shell.dispose();
				break;
			}
		}
	}
}