I wonder if this is a good place for the lock screen button, particular if you are riding your bike?
What if you only want to lock the zoom level for better viewing   I´m not sure, if I hit always the right buttom.  

it's a question on some poll ...

do you know about ability to define default action on a buttons? Just long-click on this lock button

and finally ... I think on a bike during a ride is problem hit almost everything ...

Quote from: "menion"do you know about ability to define default action on a buttons? Just long-click on this lock button

No, I didn´t know it. And yes, it helps. But in my eyes the older solution was a bit smoother. So I vote for this.  

three votes ... c'mon others, help to decide

oki, six votes (not much btw.) so function remain for now on it's place. To all who do not like, I suggest long click on zoom-lock icon and set default action of this button from list of available actions