Query containing umlauts is superscripted in search input field (IE only)

Steps to reproduce:

1. Search for anything with umlauts in the query e.g. müssen
2. In the search results page (dosearchiste.action), the query in the search input field is superscripted. Please refer to screenshot for example output.

Same problem occurred for Danish characters as well e.g. Kørestol, æÆ åÅ øØ

This problem can be reproduced in IE7, IE8, IE9.