RetainSameConnection interferes with expressions on connection managers

I have ran into this issue a few times and was planning to document it for others but John Welch summed it up nicely.

"If you have RetainSameConnection set to TRUE, and you are also trying to update the connection string through an expression, be aware the connection will not change to reflect the new connection string. Basically, the connection will retain the original value (as RetainSameConnection would indicate)."

http://agilebi.com/jwelch/2008/03/28/retainsameconnection-and-expressions/

http://connect.microsoft.com/SQLServer/feedback/details/334933/retainsameconnection-interfers-with-expressions-on-connection-managers