Export problem

Hi,

I have export problem with visual form builder free :
I created a first form, and i was able to export all fields.
Then i created a second form. When i go to export panel, both forms are displayed in the selected field. When i try to export the first form, no problem (the first form is in fact the default form selected). But if i try to select the second form, then the corresponding fields are not correctly loaded. And i cannot export them. I can only export default fields (ID, Date, IP, …).
Has anyone the same problem? Thank you in advance.

WordPress v4.4.2
Visual Form Builder v2.8.7 (free)
https://wordpress.org/plugins/visual-form-builder/