Contains and containsnot is missing in corpus assistant under special circumstances

[hebasta]

Normally you can choose eq, neq, contains and containsNot when defining a virtual corpus, for instance author contains Goethe.
It works in most of the cases, for instance here:

1. Defineauthor eq Goethe(contains is part of the drop box)
2. Search after a query
3. No results, so the user changes the corpus definition to author contains Goethe

This does not work in this case:

1. Define author eq Goethe
2. After realizing that contains (without searching between) would be better, try to change the definition to author contains Goehte
   The drop box only offers eq and neq as possibilty
   author eq Goethe has to be deleted and defined new to be able to select contains