How do I get my action line back in sequencer?

Hey, so im following a tutorial and ive seem to have lost the little blue line when im sequencing. This is a pic of the tutorial: https://i.imgur.com/MBUoKRB.png

this is what mine looks like: https://i.imgur.com/DvMT20o.png

as you can see im missing the blue line and i just want to get it back so i can finish this Dx