Uploading new form definition without closing dialog results in error

[yanokwa]

I'm not sure if this is intended behavior, but I run into it all the time when iterating on form design.

1. Upload a form with an error using "Choose one".

2. Keep that same dialog box up while fixing the error. Save the file.

3. Use "Choose one" to upload the same form.

I've looked at logs, but don't see anything obviously wrong.

[matthew-white]

I'm pretty sure this is a Frontend bug similar to #197. I think it's an easy fix (maybe even a one-liner?), so if the issue comes up often, maybe it'd be worth trying to fix it for v1.1?