Some features like hoisting and loading all previously opened tabs are not implemented in the viewer, and we'll consider adding them. Also, the viewer does store toolbar and menu customizations in the same place as the full version, so it's best not to run it on the same machine where UR itself is installed.
The viewer definitely should not take several tries to start, or ever modify the .urd file at all (the date modified timestamp on the file should not change), and should display all of the items in the database. I wasn't able to reproduce the problems you mentioned -- could you ZIP and post or send a problem .urd file to
support@kinook.com? Thanks.