Custom queries without icon disable folder menu

A folder dropdown menu that contains custom queries and does not specify an icon does not work anymore.

Steps to reproduce (in the CMS test):

1. in the console, copy the node "/hippo:configuration/hippo:queries/hippo:templates/new-document" to "/hippo:configuration/hippo:queries/hippo:templates/new-news"
2. in the console, select node "/content/documents/news", edit property "hippostd:foldertype" and change the value "new-document" to "new-news"
3. in the CMS, click on the arrow next to the "news" folder to open the dropdown menu

Expected behavior: the dropdown menu is shown as usual (since the new query "new-news" is identical to the old query "new-document")
Actual behavior: the dropdown menu is not shown anymore

Custom queries are documented at http://www.onehippo.org/cms7/documentation/development/extending+CMS7/user+interface/document+types+in+folder.html