• Open a document in a language that is not your default language, for example: https://fr.wikipedia.org/wiki/Cumul_des_mandats_en_France?veaction=edit (if you're not French).
• Assuming your browser does have a French dictionary, the article should have few to 0 red-underlined words.
• Click on a [1] reference.
• Observe suddenly almost every word is spellcheck invalidated by red lines
• Moving the cursor by keyboard arrows still keeps them invalid.
• As soon as you actually use the mouse to click for a cursor move, that is when it switches back to the correct language (or perhaps it disables spellcheck)

Not sure, but I think this is a regression.

Version: unspecified
Severity: normal