Grid with setDropMode(...) in a CustomField throws IllegalStateException Connector can only b

  1. Create a CustomField add in a FormLayout.
  2. In this CustomField, add a basic Grid, no issue when the FormLayout is detached
  3. Now, in your grid call the method .setDropMode(GridDropMode.BETWEEN) → java.lang.IllegalStateException: Connector can only be initialized for an attached Grid

Workaround found:

Set the Drop mode in your addDragStartListener

Set drop mode null in addDragEndListener

That workaround is a good practice in any case, but you could create a bug ticket about it

Ok, thank you @vital-koala