F5 or REFRESH is not workig

I apologize for the silly question, but we recently converted from P6 version 6.2.1 and are now in P6 8.3 in the client server.  Unfortunately, the F5 or Refresh does not work.  There are two of us in one project, and the loop I fix is still being seen by the other user.  I also went ahead and deleted a number of activities from the project, but they were still seen by the other user.  We literally had to both exit the project and re-enter the project before changes are seen by both users.  Is it possible the project is