RichControl has an Anchor property, which is an enumerated type whose values can be OR'd together to describe from which edges of a control's parent control it will maintain a constant distance. For example, if you put a button on a form and set the Anchor property to AnchorStyles. BottomRight , the button will remain the same distance from the bottom and right edges of the form when it is resized. Moreover, if you set Anchor to AnchorStyles. All , all sides of the button will remain anchored to the corresponding edges of the form, and the button will resize to meet these constraints.
Docking is really just a special case of Anchoring.
RichControl 's Dock property describes to which edge of the parent control a control is to fasten itself. Docking can be Top, Left, Right, Bottom, or Fill. In each case, the control is moved as close as possible to the specified edge and sized to fill that edge, where it will remain when the parent is resized. Moving a control to the bottom of a parent and setting Anchor to AnchorStyle. BottomLeftRight can simulate Docking Bottom.