Drag and drop interactions involve multiple distinct states: idle, dragging, hover-over-target, dropping, and animation completion.

• States: idle → dragging → droppable → dropped → animating

• Events: drag.start, drag.move, drag.enter, drag.leave, drag.drop

• Context for positional data

• Parallel states for multi-item drag

• Drag and Drop → Animations — Drop animation states

• Drag and Drop → Undo/Redo — Undoable drag operations

• Case Study: Collaborative Editing — Shared drag state

• Add drag reorder machine

• Add multi-select drag machine

• Add touch event handling