My Router appeared to have a problem & had stopped connecting to the Internet!
As soon as I started to investigate, a MDC message popped up (taking "focus" away from what I was doing) telling me I didn't have Internet Connection (Yes, I know, that is what I was trying to resolve before I got the Pop-Up)!
I acknowledged the message (by clicking "Close") &, before I could do anything else, it popped up again (& again & again & again & again . . . . . . .). In fact, it prevented me from doing anything else - particularly it prevented me from investigating my Internet Problems!!
Eventually I had to give it the 3-button salute (Ctrl-Alt-Del) & fully close MDC via the Taskmaster.
Only an "irritating" issue, but I hope the TomTom Software Developers do fix it at the next update!!