Flex 4 Non-editable ComboBox spark component

I recently started using the release build of Flash Builder 4, after using the betas for some time.  In the beta, the ComboBox component had a property called editable, which would allow you to edit textInput component within the combobox.  If you didn't want it to be editable, you could set that property to be false.  With the release build, it looks like the "editable" property is no longer there, and I can't figure out how to make the ComboBox non-editable.  Is there a way to do this?