Trouble changing lineups

Is anyone having trouble changing the players in their starting lineup? Normally it should give a drop down so you can select the player you want at the position. I am not getting the dropdown.
I get the dropdown menu for changing pitchers, but not hitters. I tried to shut down the computer but it is still happening.
Am I the only one?

I had the same trouble when using FireFox, but they updated it and that seemed to fix it. If you use more than one browser, try a different one. IE9 worked for me.

Did you click on "edit this lineup" at the top of the lineup page?

Yes, I am on the edit screen. It must have something to do with the recent Firefox upgrade. I find that I can change the players by doing a right-click to open up the dropdown menu. It isn't as smooth as before, but at least I'm not stuck with the same nine players under all conditions.