Expanding an OPC browser folder causes Gateway to drop the designer session

We are attempting to get an HMI program working with an old SLC processor before we upgrade to a Control Logix. While working with the OPC browser, expanding one of the data file folders creates a long delay and about half the time the designer session is dropped and will not reconnect. Could increasing the timeout possibly prevent this and where would that setting be found?

The banner for Gateway connection lost is active and states that the master and backup are available with the nodes being active but it does not reconnect. It just spins.