Cannot drag & drop element to Form elements in content

Found in

EPiServer.Forms 4.11.0

Fixed in

EPiServer.Forms 4.14.0

Created

May 10, 2018

Updated

Jun 12, 2018

State

Closed, Fixed and tested


Description

Step to reproduce.

1. Login to a CMS system that has installed Forms.
2. Create new a Form.
3. Click to publish that Form.
4. In All Properties mode, drag & drop the first element to Form elements.
5. Drag & drop the second element to Form elements.

Expected:
You can successfully drag & drop two elements to Form elements.

Actual:
At the second drag & drop, the system shows this message:
*"Could not save property, and it has been reverted. Please try again.
ContentReference: Input string was not in a correct format."*