Does cover need to be locked or rolled up only?

I have some items I'll be traveling with that are taller than my cargo bed truxport roll up cover. I was thinking of leaving the taller items near the tailgate with the cover rolled back only once or twice so other items could sit under the cover and stay secure.

Does the roll up cover either need to be locked in place or rolled up all the way to the back window or is it ok to do my scenario?

 

I don't have a cover, but it sounds like if you leave the cab end of the bed cover open, and close the tail gate end, the wind could catch your cover and pull it off.