Controlling How Child Controls Respond to Drag-and-dock Operations
Go Up to Implementing Drag and Dock in Controls
Dockable child controls have two events that occur during drag-and-dock operations: OnStartDock, analogous to the OnStartDrag event of a drag-and-drop operation, allows the dockable child control to create a custom drag object. OnEndDock, like OnEndDrag, occurs when the dragging terminates.