Because the client GUI presents a view of the state of server objects at all times, when the solution changes (after an iteration) for example, any data objects that are being viewed in the GUI will be updated to reflect the new values. This is valuable for monitoring the progress of a solution and being able to make corrections to the settings and conditions to allow you to get to a faster solution.
The downside is that this continuous updating can be expensive and can slow down the server in some situations. The solution would be to close any open scene displays, or at least those which are no longer essential.