No cursor when the content is empty

[Kasheftin]

Describe the bug

There's no blinking cursor when the content is empty & editor is focused.
There's something wrong with the .cm-cursor div height, it's zero.
Here's the trivial source code and the repro, https://github.com/Kasheftin/codemirror-no-cursor-bug.
The top line is a raw codemirror v6.0.1, it works fine, if you focus the editor, a blinking blue cursor appears.
The second line is vue-codemirror v6.1.1 using the same codemirror v6.0.1 under the hood. If the content is empty, and you focus the editor, there's no blinking blue cursor shown.

I added this as an issue for codemirror initially, codemirror/dev#1177, but since the raw codemirror works correctly, it means the reason is vue-codemirror wrapper.

Reproduction

https://kasheftin.github.io/codemirror-no-cursor-bug/

• Focus on the top line
• Blinking blue cursor is shown
• Focus on the second line
• Blinking blue cursor is not shown

System Info

Ubuntu, Chrome Version 113.0.5672.126 (Official Build) (64-bit)
Codemirror v6.0.1
vue-codemirror v6.1.1

Used Package Manager

npm

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