Hi Gents

I have built an external structure following the tutorial creating the volumes and using zz wall etc,  When I come to position a cabinet into the space it clips to the outside of the ZZ wall.  I have the double back in from the front and I have put divisions left and right but still locks onto the outside.  Every time I have tried this in the past I have the same problem.  I have attached the project which is two under stair spaces so you can see what I am doing wrong, so can you please let me know?

Thanks