title: codemirror - line numbers overlapped with code
body: <p>I'm using codemirror latest (v5.49.0). for my electron text editor app, sometimes line numbers are rendered overlapped with the text. cannot reproduce the bug because it doesn't happen always. easily it can reproduce by refreshing the app several times. Anyone have an idea? or may be this is a known issue for you? </p>
  
  <p><a href="https://i.stack.imgur.com/PzDG4.png" rel="noreferrer"><img src="https://i.stack.imgur.com/PzDG4.png" alt="enter image description here"></a></p>