My iMac won't let me delete my Dropbox

I fixed it, there was another hidden folder that I didn't find. I deleted it and now the app I believe is officially gone.

So I've tried the trick that I seen on another forum of opening it's contents and deleting plugin etc, however I keep getting the same error that I can't put the Dropbox application in the trash because it's opened. It does show me that it's missing plugins and what not. The app just asked to save my screenshot to Dropbox.... so maybe it didn't work afterall.