custom model needs scroll panel

[butler]

the panel has NO scrollbar - thus on my small laptop I could never reach the "apply" button and thus thwarted from saving the function. On my mac with a bigger screen it is reachable (barely). In this case using a space in the function name is not acceptable but the error generated is just "error" and not helpful. Worse, if you hit apply again it now says "name already exists." this logic is probably also wrong on PC but needs to be tested once scroll panel is added. Actual non functional code generates pop ups describing the problem.

[butler]

Still not sure how to get the scrolling to work but something about needing to do manually or let sizers do it… not clear wh sizer is not "doing it" at this point. On the other hand had even more issues with error capturing and reporting than for composite model editor which are mostly fixed now.

[butler]

Now fixed along with all the bugs I could find. Should be much more robust now but could still use some TLC and refactoring. Done for now so closing ticket.