All the content dissapears with 'already exists..'

When you get the message: 'This productcode is already in use' (or something close to that)
The complete product information and everything you worked hard for is gone! And you have to start over again.. hoping next time you choice the right number

Isn't there any way to leave the content when you use the code double? so you only have to change the product-code?

I'm getting so unhappy if this happends

That's because you're using the save button and not the apply one.

We'll change the behavior of the save button for next release so that it stays on the edition page when there is a problem.