The back button on my brand new Etrex 20 is not working properly. When I'm in the map and I use the joystick to move to another part of the map then press the back button instead of taking me back to the menu (like it did last week when I tried it for the first time) it takes me to the blue triangle showing my position on the map. If I press the button a second time it takes me to the menu. Does anyone know what could have caused this and how to fix it? The only thing I've done since last week is delete the map I had loaded onto the micro SD card and load a different one. This is my first GPS and I'm unsure if it's something I've done or if the device is faulty.