Occasionally, when using multiple classes (both visual and custom) in the construction of forms, there arises issues having to do with how my classes are contained one within another. This containership also has ramifications for how things look and operate (i.e., clicking form objects in certain ways or certain sequences causes not only unexpected operational behaviour, but unexpected visual behaviour as well). I don't know if you have such an environment for the form in question, but I thought it was worth mentioning.