I'm not sure if it's the same thing, but usually, holding shift while right clicking enables the context menu in Firefox.

Why do you need to toggle them? Isn't pasting and right clicking useful everywhere?

Some SPAs and other sites have useful right click actions that I want to preserve. Does this setting disable those?

(For the pasting, I agree with you. I can't think of a single reason I'd want a website to prevent me from pasting)

You do not end up losing those. Both the popup menus - the site's as well as the browser's - are shown, the latter on top of the former. Press Esc to make your browser's vanish, and you still have the site's available.

Thanks. I just toggled both of those settings.

I thought some complex web app (editor like) supports copying and pasting complex non-text structure.