Environment Variables wizard: Refresh should warn that it'll undo all changes

In Edit Environment variables shell the Refresh button undo local changes - all changes upon local variables (removed/added/modified) are commited after click on Finish button. So if someone try to modify more environment variables and then "accidentally" click on Refresh button, then all local changes are disposed and variables are refreshed from server. There should be probably some warning before this action to let the user be sure about consequences of his action.