problem: trimmed surface rebuilds the original shape in grasshopper

this is somehting that is really disturbing me for the last couple of days..I trim a surface and when I try to manipulate it, I get the result on the whole shape..as if it were never trimmed.

I attached the following picture which demonstrates a surface morph on a trimmed surface while the result is shown on the whole sphere for some reasson..what is caousing this??