Bug 16995 HoverHelp example does not create ON_TOP Shell for tooltips
The shell created to show the tooltip does not have the ON_TOP style. It causes the main window to loose focus when the tooltip is shown.
examples/org.eclipse.swt.examples/src/org/eclipse/swt/examples/hoverhelp/HoverHelp.java
for (int i=0; i<4; i++) {
			TreeItem item = new TreeItem (tree, SWT.PUSH);
			item.setText (getResourceString("Item", new Object[] { new Integer(i) }));
			item.setData ("TIP_IMAGE", images[hhiWarning]);
			item.setText (getResourceString("TreeItem.text", new Object[] { new Integer(i) }));
			item.setData ("TIP_TEXT", getResourceString("TreeItem.tooltip",
				new Object[] { item.getText() }));
			item.setData ("TIP_HELPTEXTHANDLER", new ToolTipHelpTextHandler() {
				public String getHelpText(Widget widget) {
					Item item = (Item) widget;
					return getResourceString("TreeItem.help", new Object[] { item.getText() });
				}
			});
		}
		tree.setLayoutData(new GridData(GridData.VERTICAL_ALIGN_FILL));
		tooltip.activateHoverHelp(tree);
	
		Button button = new Button (frame, SWT.PUSH);
		button.setText (getResourceString("Hello.text"));
		button.setData ("TIP_TEXT", getResourceString("Hello.tooltip"));
		tooltip.activateHoverHelp(button);
	}
	/**
	 * Emulated tooltip handler
	 * Notice that we could display anything in a tooltip besides text and images.
	 * For instance, it might make sense to embed large tables of data or buttons linking
	 * data under inspection to material elsewhere, or perform dynamic lookup for creating
	 * tooltip text on the fly.
	 */
	protected static class ToolTipHandler {