I have it set to show newsblur’s menu, but since earlier today, I’m seeing both.
What browser/OS are you using? A screenshot would help immensely, since I can’t reproduce this issue.
Found the solution. It’s not to do with NewsBlur, but Firefox.
dom.event.contextmenu.enabled = false – we get context menu from both the site & the browser
dom.event.contextmenu.enabled = true (default setting I think) – only site-specific override, if any