Drag into "+Add Block" is inconsistent

Bugs
1

Builder content link

Builder public api key
4a52b3b8ac444b998a4f90d60aa6fcc3

Detailed steps to reproduce the bug
How to Add Dynamic Editing Regions to Custom Components is helpful here

  1. create a Symbol with multiple Slots. For example, a Columns object with 2 columns and one Slot in each. Give the Slots different names (e.g. mainChildren and leftChildren) so they don’t share the same content.
  2. create a Page
  3. add an instance of your Symbol to the page; don’t add any children
  4. add some other content oustide the Symbol
  5. try to drag the other content into either of the “+Add Block” targets. Sometimes the content adds as a child; sometimes it moves to before or after the Symbol.

This happens in both the embedded and fallback editors.

Screenshots or video link
This one failed:
drag-to-add-block-1
As did this one:
drag-to-add-block-2
But this did what I wanted:
drag-to-add-block-3

1 Like