Originally Posted by Obo View Post
Yep, that fixed it for me as well when using brave browser. But as you wrote, it's probably independent of the site, but rather dependent on the payload, if the culprit was breaking spaces. I guess it took some brain work to find the issue - nice find!
Just to follow up and close this for me: The QsciScintilla widget doesn't change non-breaking spaces and is almost a drop-in replacement for QTextEdit/QPlainTextEdit. No problems in my tool anymore.