Replying to Quoting People -- Signatures

recently when i have gone to quote someone on something they say, when it takes me to the box of which i wish to reference, the signature will appear as well. Its messed.. like.. if i choose to quote the whole post the person made (along with signature) and in my box i say what ever i want to say.. and then i hit "reply" it says error: choose what of the quote you want to reference first   or something like that.

I dunno, just another flaw of the site i guess. It happens i would say 20% of the time i go to quote someone.