When in the UI editor and having an embed in place, the user can create empty embeds by clicking enter. This is the same at least on Chrome and Firefox. This is a regression from 1.3. where this behaviour was not in place.

Steps to reproduce:

1. Clean install of 1.4. (Studio / Platform)
2. Edit folder
3. Embed an item
4. Click enter a few times
5. Observe empty grey box (embed with no source?)
6. Add new embed
7. On select observe the loading graphic on empty embeds

Screencast demo: https://www.youtube.com/watch?v=4N8kJ3bYzDY&feature=youtu.be