Why is my quick selection changing after I release the left click? (Images inside)

While still holding down left click http://ift.tt/15u9euX

Selection after releasing left click http://ift.tt/1tc3FfK

This is doing my head in, I only just found out about this tool, it seemed perfect, but now it keeps doing this. I feel like I checked an option or changed something simple that is screwing it up but I have no idea and google hasnt helped, all the videos I have seen everyones tool works fine.

Appreciate the assistance :)