Can’t increase partition size of cloned volume in Mac OS X 10.11 (El Capitan)
In general, when you use those hardware-only cloning devices—like that ICY BOX you mention—you end up in situations like this. Perhaps there is a cleaner way to recover from a situation like this, but in my experience what you are attempting to do just won’t work; hardware cloning like that is strictly one-to-one as far as volume size goes. And if the target volume size is larger than the source size, the situation that you are in happens; the volume is cloned but the maximum destination volume size becomes exactly the same as the source volume size.

What I always do for cases like this—cloning smaller drive to larger drive—is to hook up the new drive to the machine in some way (such as an external USB enclosure) and then clone it via rsync or Carbon Copy Cloner. This strictly copies OS level data from one device to another; not partition data/info so this always works right off the bat.