Drag and Drop Solution - Sample with Multiple Correct Targets with drag off and return plus a lot more
Here's a sample Drag and Drop that provides almost everything people have been asking for.
1. Any number of targets can be correct for any object.
2. Objects not dropped on target are returned.
3. Targets can be cleared of dropped objects.
4. Multiple objects can be dropped on a single target.
5. On Try Again, it can clear or maintain the previous attempt.
6. Provides feedback that is specific to incorrect answers.
7. Answers can be saved and made available later in the course.
8. Allows partial, multiple, or very complex combinations of Correct answers.
9. Dropping objects can automatically resize or reshape.
10. Can enforce a minimum requirement for number of selected objects before submission is permitted.
There are six examples, and since different ones highlight different features, not every one contains all the features.
It contains explanations of how it works, and instructions for modifying it.
Note: Since it uses a Pick one interaction, regular Drag and Drop options (like objects appearing one at a time, or the various stacking options) are not available through the SL menu, but must be created.
Feel free to use as is, or study it and take just the principle that meets your need.
You can see it action here:
EDIT: I've changed it to load in 360. Sorry about the confusion.