I think you have your not equals backwards. it should be != not =!. Also, please post your actual scripts/expressions on the forum and not screenshots when possible. It makes it easier for others to view, copy and paste, and test. Once you paste the code, you can highlight it then push the performatted text button which looks like </>. This will make your scripts very easy to read.
@Duffanator@dkhayes117. It worked! I thought the problem is with binding and visibility property, not this very simple sign which I completely ignored!! Anyways thank you very much!!!