BUG: Cannot add components to placeholder without saving first

[jeppeskovsen]

Description

In the Experience Editor when I add a component containing a placeholder, and I try to add a component to that, I get this error:

To make it work, I have to add the component and save. Then I can add components to it's placeholder. It's like it doesn't register that the component I added contains a placeholder until I save.
Will also mention that my list of allowed controls does not work either, when this error occurs.

Your Environment

• Sitecore Version: 9.1
• JSS Version: 11.0.2

[aweber1]

Just noting that I was able to reproduce this with Sitecore 9.1.0 and JSS 11.0.2.

Reproduction steps:

• In content editor, in a JSS app, create a new item/route using JSS App Route template.
• Edit item in Experience Editor
• Add Styleguide-Layout component to Main placeholder (don't save)
• Add new ContentBlock component to jss-styleguide-layout placeholder
  • Create new ContentBlock datasource item
• Experience Editor should pop an alert An error occurred.
• Browser dev console shows the same as the screenshot provided earlier in the thread.

[sc-illiakovalenko]

@jeppeskovsen Fixed in #343