Where does your idea go when it has already been forgotten?

I think that it isn’t forgotten just have to have someone or something to recall it back to your mind. It in your memory where everything you’ve ever done is.

gone but never forgotten 

Some ideas go into the back of your mind to be recalled later but others are just gone.

The idea does not stay with you if you did not note it down. It will pop to someone elsewhere. You may wonder when the person stole your idea.

When my idea is forgotten by me. Some other person will have the same idea. So ideas are not forgotten.