It's a bad idea to use public variables in the first place. You should rethink your design and get rid of them.
Anyway, a public variable becomes hidden when it's passed as a parameter by reference.

>Hi all, I'm fighting against a strange behaviour I cannot explain.
>
>I have a main exe file which declare a certain number of variables, then calls an app which refers to those variables
>
>well, one of those "zIdTrm" is undefined.
>I placed i disp memory just before the calling line of code and another one on the head of the called app
>
>this variables i signed as public with the right value on the first while it is marked as (hid) but with the same value after the second disp memory
>
>what the hell can it be ?