(def top-frame
  (doto (Frame.)
    (.addWindowListener
     (proxy [WindowAdapter] []
       (windowClosing [e] (.dispose top-frame))))
    (.add (doto @(def top-panel (Panel.))
            (.setLayout (BorderLayout. 5 5))
            (.add "North" (doto @(def choice (Choice.))
                            (.add "None")
                            (.addItemListener
                             (reify ItemListener
                               (itemStateChanged [_ e]
                                 (send timers change-timer (.getItem e))
                                 (.validate top-panel))))))
            (.add "Center" (doto @(def timer-panel (Panel.))
                             (.setLayout (GridLayout. 0 2))))
            (.add "South" (doto (Panel.)
                            (.setLayout (GridLayout. 0 2))
                            (.add (doto (Button. "Add")
                                    (.addActionListener
                                     (reify ActionListener
                                       (actionPerformed [_ _]
                                         (add-timer (.getText add-name)))))))
                            (.add @(def add-name (TextField.)))))))
    (.pack)
    (.setVisible true)))