LuceneSearch doesnt work with GermanAnalyzer

Steps to Reproduce:

• configure GermanAnalyzer in xwiki.cfg

  xwiki.plugins.lucene.analyzer=org.apache.lucene.analysis.de.GermanAnalyzer 

• be sure to set in your xwiki profile 'show hidden documents' to false.
• got to search page and enter a search term that should produce results, e.g. 'welcome'

Expected results are some hits and on a GermanAnalyzer there are no results.

debug log shows that the query was:

//GermanAnalyzer:
query [+((+(ft:welcom title:welcom name:welcom filename:welcom) +hidden:fals)^4.0) +wiki:template] returned 0 hits

It seems that the stemming of the analyzer also stems the 'hidden' attribute but this is configured to be a not analyzed field (see com.xpn.xwiki.plugin.lucene.internal.AbstractDocumentData)