About Handles
Handles are graphical objects that are used to manipulate geometry during creation or redefinition in realtime. Using your mouse, drag the handles to resize, reorient, or move feature geometry. Snap handles to existing geometric references or to user-defined grid increments. Your changes display dynamically in the graphics window.
Handle display changes at specified intervals to acknowledge your actions, and are used in conjunction with the left mouse button, SHIFT and CTRL.