If you are in a view that has a number of unread documents where you are not allowed to read them, then hitting the Tab key or selecting Next Unread Document will present the dialog below. Until you go through all the unread documents, it continues to present the message without opportunity to break out of the loop.
Recommendation - provide a Cancel button as well.
I inadvertently hit Tab within THIS database after reading the last unread message and encountered the problem.
A new spr is open for this issue KLSG7JJ9H9 Next Unread Document behavior not good in a view you have some document where you are not allowed to read them .
And More details is needed from you:
Which view are you using when this problem occur,what is your ACL and Roles to this application?
What kind of documents you are not allowed to read? It seems difficult to meet this dialog on my environment.