video player control question

Hi all - I am returning to Storyline after a couple of years away from the eLearning game.  As I am building a new course, I am trying to include videos (4 videos in one storyline file, each about 3-5 minutes long).  For the videos, we want people to watch them in their entirety before the next slide will be unlocked.  I want to allow people the ability to pause/play the video, as well as rewind if they need to - but I don't want people to be able to fast forward (unless they have already completed the video).  I was able to set the player controls (i.e. the storyline player, not the video player) to "allow user to drag after completion" - but this does not allow for people to be able to rewind during the first run through.  If you're watching a 5 minute video, you don't want to have to wait several minutes to be able to go back to something you missed in the first couple of minutes.  

Is there some way I can get the functionality I want?

On a side note - can someone tell me what this button does?? 

I thought it was a refresh slide sort of button that would allow someone to at least go back to the beginning of the video on the slide - but after trying to click it, it seems to do nothing... can I get rid of it so people aren't wondering what it is?

Thanks!

Wanda