The source for the top-most element on the event route stack at which two logical trees diverge.

在事件路由堆叠中，新增开始分枝成两个逻辑树状结构的最上层项目。

youdao

The source for the top-most element on the event route stack at which two logical trees diverge.

在事件路由堆叠中，新增开始分枝成两个逻辑树状结构的最上层项目。

youdao