Control Points are the dots located in the corners or along the segments of a selected object that allow you to edit its shape.
Start Points and Stop Points are Blue
Center Points are Green
These can be toggled on/off in the Options menu.
Moving these Control Points will change the shape of the element being edited.
Control Points on the Bounding Rectangle are displayed as darker dots on the corners that can be used to edit the object.
Bounding Rectangle
Show Control Points: Trace
Show Cut Order Numbers: Trace
Show Start Points: Trace
Snapping to Control Points: Trace