The InvalidOperationException error occurs when the FormID or Data Source field is empty on the Mvc Form rendering in Layout Details.
After applying this patch the empty form (which ID is defined in the Sitecore.Support.138241.config file) with additional information will be displayed instead of the error.
The default item path for the empty form is /sitecore/system/Modules/Web Forms for Marketers/Sample forms/Empty form.
It can be customized depending on special needs or it is possible to select another form using the WFM.EmptyForm setting in the mentioned configuration file.
This patch is licensed under the Sitecore Corporation A/S License for GitHub.
Downloads are available via GitHub Releases.
