I had a somewhat similar situation to what Dan comments. I has a tab with Facebook opened. I closed it and continued browsing, but then i started hearing the "Message received" sound. I concluded that the website was still opened even when the tab was closed.
I had a somewhat similar situation to what Dan comments. I has a tab with Facebook opened. I closed it and continued browsing, but then i started hearing the "Message received" sound. I concluded that the website was still opened even when the tab was closed.