Curiously enough, despite having 76 waypoints appearing on my map page my Waypoint Manager displays only a list of 19.
Weird, I've just checked my waypoint manager on my Etrex 20 and all 42 of my waypoints show up. Maybe the 10 works differently to the 20?
Apparently with the Etrex 10 only 19 of the nearest waypoints to where you are at the time appear in the Waypoint Manager. To see all of the waypoints you have to go to the map. You can, however, do a spell search and you'll find any waypoint, but it won't be on the waypoint list unless it's amongst those nearest to you.
I recently bought an etrex 10 and can confirm that having loaded about 30 caches onto it, when selecting go to and then geocaches it only displays the first 19. REALLY irritating if I want to navigate to any of the ones after the closest 19 using the etrex. I can view them on the map and then select one but that's very fiddly when I've loaded a bunch from the same area for a cache blitz...