class TrackedPage: Page {
    calls: Object
    function moveToWindow(self: TrackedPage, window: Window): Page {
        self.calls.increment()
        return Page.moveToWindow(self, window)
    }
    function moveTab(self: TrackedPage, position: Number): Page {
        self.calls.increment()
        return Page.moveTab(self, position)
    }
}
class Actions {
    list: Column
    function insert(self: Actions, event: Event): Unit {
        self.list.insert(1, TextBlock("插入的新对象"))
    }
}
calls = ui.state(0)
list = Column(0, 8, TextBlock("第一个子项"), TextBlock("最后一个子项"))
actions = Actions(list)
button = Button("在位置 1 插入 Block")
connection = button.on("click", actions.insert)
shared = Column(24, 16, TextBlock("拖动 Tab 重排、移入另一个窗口，或拖出独立窗口"), TextBlock("Page 方法调用次数"), ui.textOf(calls,"value"), button, list)
first = TrackedPage(calls)
first.title = "A · 共享内容"
first.render(shared)
second = TrackedPage(calls)
second.title = "B · 单独内容"
second.render(Column(24, 16, TextBlock("这是 B，Page 身份随 Tab 移动保留")))
third = TrackedPage(calls)
third.title = "C · 同一对象"
third.render(shared)
other = Window()
other.resize(720,520)
other.setTitle("Tab Target")
other.moveTo(1700,80)
target = TrackedPage(calls)
target.title = "目标窗口"
target.render(shared)
target.open(other)
first.activate()
ui.window().resize(800,600)
ui.window().setTitle("Tab Source")
ui.window().moveTo(50,80)
ui.window().focus()