[galaxy-user] How do I remove "Histories shared with you by others"?

Hello - I am trying to clean out my "Histories shared with you by others" page on the main public Galaxy server. I would like to remove old histories shared with me. I have tried two methods, neither of which allow me to remove these histories: 1. clicking the check box to a history shared with me, then clicking "Unshare" at the bottom of the page 2. clicking the drop down menu and then selecting "Unshare" In both cases, I get the error message "History is not owned by the current user". This behavior appears to be referenced in another recent thread from the sharer's side (http://user.list.galaxyproject.org/Trying-to-quot-unshare-quot-a-history-in-...). Any ideas on what is going on here? Best regards, Casey