I just searched for in trockenen Tüchern, which yielded no results. The first suggestions were:
Place your search terms in quotes to search for a phrase:
"in trockenen Tchern"
Search within a specific set of tags:
[tag] in trockenen tüchern
[tag] [another-tag] in trockenen tüchern
The ü in the search text has been preserved in the “tag search” suggestion but not in the “phrase” suggestion.