LT doesn't work on latest Safari

1

Environment

MacOS Sonoma 16.4, Safari Beta 18

Reproduce source code

HTML 
<!DOCTYPE html>
<html>
  <head>
    <title>Page Title</title>
  </head>
  <body>
    <p>This will check spelling</p>
    <div contenteditable="true" spellcheck="true" style="border:1px solid grey;"></div>
    <br>
    <iframe srcdoc="<!DOCTYPE html>
      <html>
      <head>
      <title>Page Title</title>
      </head>
      <body>
      <p>This will NOT check spelling</p>
      <div contenteditable='true' spellcheck='true' style='border:1px solid grey;'></div>
      </body>
      </html>
      "/>
  </body>
</html>

Reproduce steps

  1. Open any html editor online site (jsFiddle for example)
  2. Paste the above code to HTML section and run
  3. Enter some text into the first text box, LT is working as normal
  4. Enter some text into the second text box, LT doesn’t show anything

Additional info

This behavior can also be reproduced in Safari 17.6

2

Thanks for the detailed report, I’ve opened an issue for our developers.