Duplicating problem! Solved

Ok, I have got an object that I duplicates with Shift+D. It works fine, and i hides the duplicated object in another layer. but when i go to the other layer and starts editing the duplicated object, but when i go back to the first layer, the original object is edited too!:confused:

Can someone tell me a solution for this problem?:smiley:

Thanks in advice!
Attchar

EDIT: Found the solution, i seems to have duplicated with Alt+D:o