Whenever a code block dialog is opened, the code is first rendered with a very too-narrow line height (that causes text to almost overlap with other lines). Then after a split second, it expands to the proper line height.
Description
Description
Event Timeline
Comment Actions
Works for me now, e.g. at https://www.mediawiki.org/wiki/Snippets/Auto-number_headings?action=edit.
Checked in Firefox 98 and Chromium 99 (macOS).