Thanks for this suggestion, that's a good idea, I can see this would be helpful sometimes. Unfortunately this would mean adding another switch button on the map - we're trying to keep the map as uncluttered as possible and it's very tempting to add lots of buttons! I'll have a think about how we might be able to do this.
In the meantime I've added this to our Feature Requests list (number 73), where anyone interested in it can vote for it.
A useful feature would be to be able to lock the route map while still being able to dd custom symbols and labels as a custom layer. See previous request.
I was just editing a published event route to add the symbols for aid stations, etc and inadvertantly auto-plotted and changed the route significantly. If we could lock the route map while still being able to add these symbols and labels it would be helpful, especially with large and crowded maps for tours/races etc.