Overlapping-alpha transparency mess after unjoing planes


I pressed the P-key and seperated all planes by loose parts to edit each of them individually.

Now I finished editing them, I rejoined them again. But the result is atrocious;
overlapping transparency is messed up and it looks nothing like it was before I unjoined the planes.

Is there a way to rejoin all the planes and get their nice overlapping-alpha tranparency back ?

(I’m a newbie and sorry for my English).

We have no idea what your problem is as you are the only person here who can see anything useful.

For support please ALWAYS supply a link to a demo blend file that clearly demonstrates the problems you are having. Without that we are all working blind !