Fix #195: Pressing and dragging outside of an item in the navigation …

…pane still switches to that page

ModernWpf/Input/InputHelper.cs

@@ -130,7 +130,11 @@ private static void OnMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
                 }
                 else
                 {
-                    RaiseTapped(element, e.Timestamp);
+                    var elementBounds = new Rect(new Point(), element.RenderSize);
+                    if (elementBounds.Contains(e.GetPosition(element)))
+                    {
+                        RaiseTapped(element, e.Timestamp);
+                    }
                 }
             }
         }