My class libraries look something like:

txtBase
  txtStd
    txtFrame
      txtApp

In the Framework level of my libraries, I'll define a CSZ container class, which takes a Zipcode and fills in the City and State. Then,
I'll subclass it at the App level. However, it is still using the
textboxes from the Framework level, rather than the App level. Is
there any way to subclass a container class and get it to pick up
the "correct" user interface elements?

Or do I have to break the behavior out into a custom class, and
just use the textboxes at the correct level, rather than a subclassed
containerL