What option is being clicked at @1:23 of this video?

[kingston123]

In this unclear CATIA cat shape tutorial youtube video , At @1:23 person selects the link and click something which changes the line into dimensional line. What is that option called?

 

[MrCATIA]

@1:23 the Construction icon is clicked in the Sketch toolbar which changes the vertical line into a construction line (dashed)

from 1:24 thru 1:30 the vertical line is constrained to be coincident with the centerpoint