Hello! Thanks a lot for the review! :)

Unfortunately those are both things that Firefox does not allow. In the current way Firefox add-ons are made (WebExtensions), they cannot remove from the context entries that do not belong to themselves.

Clicking the SSS context menu parent "Search for" also seems to always do the default behaviour, which is to simply open the sub options, so SSS isn't even notified of a click there. Sorry I can't be of more help!