[otrs] Bulk feature does not work in locked tickets

I wanted to use the bulk feature in my locked tickets, but there is an error message, saying "You need min. 1 selected ticket". However, I have selected several tickets and still it doesnt work!!! It works in the "IN" folder, though... Further more, my Generic Agent doesnt work either with the bulk feature! It works with deletion of my spam group "junk", all fine, but when I select in the IN folder some messages and use the bulk feature to move them into the Junk folder, they do NOT get deleted!! Is this because they are locked??? How can I delete them, even though they are locked? thanks, marc