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
public void mouseExit(MouseEvent e) {
					if (tipShell.isVisible()) tipShell.setVisible(false);
					tipWidget = null;
				}
				public void mouseHover (MouseEvent event) {
					Point pt = new Point (event.x, event.y);
					Widget widget = event.widget;
					if (widget instanceof ToolBar) {
						ToolBar w = (ToolBar) widget;
						widget = w.getItem (pt);
					}
					if (widget instanceof Table) {
						Table w = (Table) widget;
						widget = w.getItem (pt);
					}
					if (widget instanceof Tree) {
						Tree w = (Tree) widget;
						widget = w.getItem (pt);
					}
					if (widget == null) {
						tipShell.setVisible(false);
						tipWidget = null;
						return;
					}
					if (widget == tipWidget) return;
					tipWidget = widget;
					tipPosition = control.toDisplay(pt);
					String text = (String) widget.getData("TIP_TEXT");
					Image image = (Image) widget.getData("TIP_IMAGE");
					tipLabelText.setText(text != null ? text : "");