Took the D700 to a soccer game last night. I was playing around with the different autofocus options trying to see which one worked best for me. I would go into the menu, change a setting, shoot off a bunch of shots... and repeat to try something different. On two seperate occasions, when I went back into the menu system, I lost the ability to navigate up/down through the menu system. I found the problem would disappear by just turning it off and back on. Has anybody else run into this? I've changed settings a lot to try different things since I got the camera but this was the first time I had experienced anything like that. Did I accidently move a button or switch that would limit your navigation that I'm not aware of?