This is NOT a specific current problem, but a request for general troubleshooting information. I know, both from reading KB articles and bitter experience, that one should not add multiple extensions that have the same purpose - Do Not Track extensions, for instance. My question pertains to FF's internal settings vs. extensions that expand upon them, e.g. the FF Block Pop-ups setting vs. an enhanced Pop-up blocking extension - are they going to conflict/confuse? Should one turn off the FF setting before installing the extension? Do we trust that the extension will change the setting appropriately? Is all this checked before an add-on is approved for the AMO?