Edge 830 screen affected by rain

Went for my first ride in proper rain since acquiring my Edge 830 and spent a very frustrating ride where the water droplets on the screen either from the rain or dripping from me were affecting the screen. Variously changing the visible screen, it also changed the map zoom but most alarmingly it "pressed" the cancel ride button and I was lucky not to lose the ride. Made for a most frustrating ride having to stop several times to either change the screen or very carefully cancel the "cancel ride" instruction. Anyone else having this issue and especially does anyone have any idea how to stop this from happening? If it is a design fault I think I will be looking to return this to Garmin!