Flex - ComboBox has lines around it

Question

I'm stumbling my way through designing my first Flex app, using Flex Builder 4 Beta 2. I'm trying to use a ComboBox, but they always seem to have lines around it and I can't figure out how to get rid of them. The ComboBox looks like this:

http://www.freeimagehosting.net/uploads/a1cde1d098.png

All I did was drag the ComboBox from the Controls section in the Design section of the UI onto the screen. I haven't changed any settings, no special css, just used the default ComboBox and this is what I get. Any ideas? Thanks!

Answer 1

Looks like it was a bug in the beta. Now that the full version is out, we've upgraded to Flash Builder 4 Premium and I no longer see this problem.