Hi John,
That sounds strange, not sure why this is happening for you in your acccout. I did do a quick test in my own account, I created a new screen, added a grid based off the Customer table, I then added a couple of dropdown fields and made the grid "Editable". John, would you mind turning on the MethodSupport User for your account so I could take a look at your screen? Please also let me know which screen this is that you are attempting this with. I am thinking there is something you have done on your screen that I might not have.
-Ben
Here is a screenshot of the Grid from the Feb Release (FYI - I highlighted "stage" in the URL, currently this is only for the February Version):
