mail attachments subgrid bugs (crm 2013)

hi all.

when opening an incoming email with several attachments, while navigating through the attachments sub-grid (clicking in the arrow to the right) and reaching the end of the list, the arrows completely disappear, making it impossible to go back to the first attachments.

any ideas on why this is happening and is there a way to workaround this?

I'm using CRM 2013 SP1 w/ UR1, on-premises.

Thanks in advance,