mozilla-services
Take Screenshot context menu item missing on sites with frames
Firefox does not display a context menu for taking screenshots when viewing a site that uses frames.
https://docs.oracle.com/javase/7/docs/api/ is an example site
Seems the extension can't take a screenshot of a frameset as a whole (there's a message to that effect when you use trigger the extension from the Page Actions menu in the address bar).
Anyway, the fact that each frame has a different scroll height is likely to make that a hard site to screenshot.
If you wanted to screenshot an individual framed document, the context menu contexts are defined here:
https://github.com/mozilla-services/screenshots/blob/master/webextension/background/startBackground.js#L40
On MDN, it says that frame refers to an iframe, but maybe adding frame would work for traditional frames, too??
https://developer.mozilla.org/docs/Mozilla/Add-ons/WebExtensions/API/menus/ContextType
Until someone gets a chance to test that out, your best workaround might be
right-click the framed page > This Frame > Open Frame in New Tab
and then screenshot it there.
