Multiple windows cause the "close" event to be triggered multiple times

[ssnangua]

index.html

<script>
  const win = nw.Window.get();
  let close = false;
  win.on("close", () => {
    alert(close);
    if (close) win.close(true);
    else close = true;
  });
</script>

main.js

// When there is only one window, it works fine:
//      first time: alert `false`
//     second time: alert `true` -> close the window
nw.Window.open("index.html");

// When there are multiple windows, closing any window will trigger the "close" event twice, and then automatically close the window:
//      first time: alert `false` -> alert `true` -> close the window
nw.Window.open("index.html");
nw.Window.open("index.html");

[ssnangua]

Currently, I solve this problem by adding a closing status. But if this is a bug, hopefully it can be fixed.

<script>
  const win = nw.Window.get();
  let close = false;
  let closing = false;
  win.on("close", () => {
    if (closing) return;
    closing = true;
    alert(close);
    if (close) {
      win.close(true);
    } else {
      closing = false;
      close = true;
    }
  });
</script>

[ayushmanchhabra]

@rogerwang Is this a bug or intented behaviour?