Contours > Shuffle Curvature Lines is the rearrangement of black or orange curvature lines that were generated by Contours > Detect Curvature, or the conversion of a black place-holder line into an orange panel-demarcation line.
The controls are:
Mouse Action group - controls the behavior of the mouse in the Viewing Area.
Subdivide Path radio button - an additional black place-holder will be inserted perpendicular to the black or orange line you click.
Flip Path radio button - the black place-holder that you click is moved to run between the other two corners of the quadrilateral in which it resides.
Promote/Demote Lines radio button - the black place-holder that you click is promoted to an orange panel-demarcation line, and the orange panel-demarcation line that you Ctrl-Click is demoted to a black place-holder line.
OK button - saves the Shape object with modifications to black place-holder lines and orange panel-demarcation lines, and closes the dialog.
Cancel button - closes the dialog without saving any changes to the Shape object.