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
tipLabelImage.setImage(image); 
					tipShell.pack();
					setHoverLocation(tipShell, tipPosition);
					tipShell.setVisible(true);
				}
			});
	
			/*
			 * Trap F1 Help to pop up a custom help box
			 */
			control.addHelpListener(new HelpListener () {
				public void helpRequested(HelpEvent event) {
					if (tipWidget == null) return;
					ToolTipHelpTextHandler handler = (ToolTipHelpTextHandler)
						tipWidget.getData("TIP_HELPTEXTHANDLER");
					if (handler == null) return;
					String text = handler.getHelpText(tipWidget);
					if (text == null) return;
					
					if (tipShell.isVisible()) {
						tipShell.setVisible(false);
						Shell helpShell = new Shell(parentShell, SWT.SHELL_TRIM);
						helpShell.setLayout(new FillLayout());
						Label label = new Label(helpShell, SWT.NONE);
						label.setText(text);
						helpShell.pack();
						setHoverLocation(helpShell, tipPosition);
						helpShell.open();
					}
				}