TYPO3 Core

I can reproduce this with words on the page like überhaupt, Ärmel etc. But words like Brühe, is not a problem.
I have also tested with danish special chars like: æøå Words starting with special chars like: Æble doesn't work, but words like rød do.

So it's a problem when words starting with a special char.

I have found the problem, but not a solution yet.

$parts = preg_split('/' . $regExString . '/i', ' ' . $str . ' ', 20000, PREG_SPLIT_DELIM_CAPTURE);

This line (Line 799 SearchController.php) doesn't find a match, to highlight, when starting with a special char like Ü or Æ, but if the text is with lowercase ü and æ it does, if there is a match in text of course. The `/i` modifier should make it case-insensitive, but doesn't seem to work like expected.

Will see if I can figure out a solution.

Thanks to @Oliver Hader and @Frank Nägler for pointing me in the right direction. The solution was smaller than I expected.

PR will come asap.

Patch set 1 for branch 11.5 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/76894

Patch set 1 for branch 10.4 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/76895