Chrome has a some nice developer tools. OP probably right-clicked the popup and got the element name, and from there knew exactly what to target.
Just to make it known, this particular set of tools isn't chrome exclusive and Firefox also has these features.
In Firefox, right click the element and select "Inspect Element". This will then show you the DOM, with the element higlighted. Then right click the hilighted element and click "Delete Node". Alternately, click "Web Console", and then type in the same command as from the example above.
Sorry, the link I followed did not show this popup, and I'm not sure how to link to a version without it. That is quite annoying.