antvx6思维导图使用@antv/x6-plugin-keyboard时报错

[hanfei7788]

Describe the bug

graph使用@antv/x6-plugin-keyboard时，graph.use(new Keyboard());后，当鼠标拖动出浏览器后，会报错Uncaught TypeError: elem.getAttribute is not a function

Your Example Website or App

null

Steps to Reproduce the Bug or Issue

鼠标按下，拖动到浏览器外，就会稳定报错

Expected behavior

修复bug

Screenshots or Videos

No response

Platform

Windows
Firefox

• Version: 2.11.1

Additional context

No response

[x6-bot]

👋 @hanfei7788

Thanks for opening your first issue here! If you're reporting a 🐞 bug, please make sure you include steps to reproduce it.
To help make it easier for us to investigate your issue, please follow the contributing guidelines.
We get a lot of issues on this repo, so please be patient and we will get back to you as soon as we can.

[hanfei7788]

更新下说明，只有在火狐最新版本才有这个问题，Google浏览器没有问题