On my Windows Vista some object properties cannot be changed
This problem can be cured by running Mediator at least once as an administrator. On Windows Vista this is done by browsing to the Mediator directory inside Program Files, then right-click the file “medi8or.exe” and choose “run as administrator” from the context menu.
When Mediator has finished loading you may close the program again and run as you normally would. This only needs to be done a single time regardless of the number of users on the computer.