This plugin is exactly what I need for my site. Thanks so much for taking the time to put it together. I noticed a bug sort of thing and managed to fix it myself and wanted to bring it to your attention.
When creating a new form, the "Post Type" drop down showed everything in one selection all in one row. So it forced me to select everything at once instead of a single post type.
So I went looking and found the error! In the admin-forms.php file in the admin folder of the plugin -- this line here (around line 70-ish)
echo '<option'.$selected.' value="'.$slug.'">'.$post_type->labels->singular_name.'</option';
You are missing the end > there after option. The line should be like this:
echo '<option'.$selected.' value="'.$slug.'">'.$post_type->labels->singular_name.'</option>';
And tada! It shows up as a full list and I can select on post type at a time!
I'm still testing this out and seeing what works. If I manage to find more fixes, I will report them to this same thread here as a reply to myself.