Why it should have permission to modify privacy settings now?! What's required by specific features could be given by telling user what should be, and how to be edited, or at least provide an option to let extension asking users who needs these features to allow these permission.

--------
Edit 1: Thanks for your patiently reply. Despite that the permissions are required, this extension's context support helped me in time to perfectly experience FF Context feature.

As for granting permission, there's a extension called "SiteDelta Highlight" on AMO you could refer to. Click into its settings page, which displays prompt "Advanced features (that require additional permissions) are disabled." with a button "Enable advanced features...".
Then click on that button, Firefox will prompt it requires additional permissions. So I think it should be able to grant several parts of permissions separately.

And a few advice:

1. Add context to directly "move to container" rather than only "copy to"

2. Ability to select multiple domain / multiple cookies at the same time

3. Every button in the bottom has hang-over tool-tips except the first one from left (and the forth, well it's easy to guess it is for donating). So... the first button with a trash bin icon is so disturbing I don't know what scope it applies to, neither know if it will ask me to sure before doing something.

4. Right-click context menu is not fully visible when click on item close to window border.

5. Why I couldn't copy expired cookies to other container? if it's exist when I access its website it would seem to be refreshed, so it maybe useful, why can't move it?