Parameters mouseDrop in GraphObject class

Good afternoon. How do I find out which group the node was pulled from? There is no group parameter in the event that handles pulling from a group.

Good morning.

First I should point out that dragging is the moving or copying of a collection of Parts, not just one Node. That collection is the DraggingTool’s https://gojs.net/latest/api/symbols/DraggingTool.html#draggedParts or
https://gojs.net/latest/api/symbols/DraggingTool.html#copiedParts.

Those moved or copied Parts might be in different Groups or they might be top-level Parts. They might be in the same Group that you are considering adding them to.

So you can see which Group(s) they may be members of before you remove them by calling https://gojs.net/latest/api/symbols/Group.html#addMembers to add them to a Group.

I don’t quite understand how I can get the Group from which I pull the node?

The Part.containingGroup property

Part.containingGroup return me null, but I pulled the node out of the group and want to get from which one

That’s why I said you should remember the containing Group(s) before removing anything from it (or them).