Backup Selection lists no longer showing shares

I've been using BE 2012 for a few weeks.  Until recently Backup selection lists would list shares on the server along with local drives etc.

I'm trying to create new backup jobs and edit existing backup jobs.  The Backup Selections list on the browse tab does not list the shares on the server.

Am I imagining things?  I'm sure that I could see shares previously.  The selections detail tab shows shares that are being backup up on existing jobs.

How do I make the shares appear again on the browse tab?

Thanks.