pre uncollapse form portions for validation errors

I don't know whether to classify this as a usability bug or a feature request, but I noticed it while I was working on a project.

If you expand a collapsible section of a form, and fill in a field incorrectly that makes it fail validation and result in a call to form_set_error(), I've noticed that you get the drupal_set_message() message for the part of the form that threw the error, but that part of the form is still collapsed when you get returned to the form. I'm thinking it might throw some people off when they see the error message, because if the offending part of the form is collapsed, the form element for that field will not have the pretty red highlighting to indicate to the user "Hey, I'm the one you filled out incorrectly. Correct me."

Now, I know its possible for me to perhaps modify my form generating code to make sure it doesn't get collapsed, but it might make more sense to do it at the level of the API's implementation rather than at the level of code that uses the API.