Moving Files From Shared Briefcase Disabled

[kbigger]

I have a group of users with a shared account, in addition to their own personal accounts. The shared account is not owned by any in the group due to frequent comings and goings of their staff. The briefcase is shared administratively to a select few "admins" and "managers". All others are "viewers".
It is possible to Move a file from the personal briefcases to the shared account but the reverse Move is disabled. Right-click a file in the shared briefcase and the Move is greyed out.
Is this function by design? DnD works though...