File emails in Shared email folder

File emails in Shared email folder

Hi, I am unable to allow users to collaborate in Shared email folders:
  • User 1 shares a folder let's say "SharedTopic" with full permissions
  • Users 2 and 3 can see this folder but are unable to add emails to this folder or search in this folder.  
For example, as user 2 or 3:
  1. select an email and press the Move To button, the shared folder never appears in the list so the email cannot be added to the shared topic folder.
  2. Search.  Even if the shared folder is selected, the search does not search in this folder, shows no results, whereas searching as user1, plenty of results are shown.
 Is this supposed to work, or should I but doing it another way?

thanks,
Jon