Detached Chrome extension

Hi,

I'm creating a Chrome extension and I would like my popup.html window to be detached from the icon I click. For example, when I run my Adobe PDF extension, the menu that appears is below my bookmarks. How can I control that? I don't want to see the little arrow coming down from my icon, I don't want any border. I just want my popup.html below the bookmarks.

Thank you so much!