With GW8SP1 a problem came back that had been fixed in the past.

Using GW8sp1 Client on Citrix Terminal Servers document integration
doenst work correctly.

Dependant on the number of users or the load of the Citrix Server
opening Excel documents from the gw-lib will result in an error message
(before opening) that Groupwise can't control excel and document have to
put back manually after closing.

Doing the same on the server if no other users or less users are online
I can open documents without this message.
We had similar problems in the past with first version of GW7.