Minimize data usage in Mobile host when not open or disconnect host when closed

I've used up my data several times now after connecting to a Control session and closing the window for the connection. The app keeps me connected, however and hours later I leave WiFi and my data is eaten very quickly. But I don't open the app at all during that time. The host app should not need to pull data like that when it is not in use, and preferably closing the client should disconnect my host instead of leaving it open in the client app. I don't actually use the app to view sessions, I use the site.