NX200 focusing question

I recently sold my NX11 and bought an NX200. Now I have one question: I half-press the shutter button to focus then press to take one picture. After taking that picture I don't release the shutter button but keep pressing it halfway with the intention to take another picture without refocusing. This worked with my NX100 and NX11 and all other cameras I owned before but the NX200 refocuses anyway. I haven't found a way to disable this. Can somebody help me?