I've been having good experiences with Pale Moon, especially latest 11.01 build and WSA-E, and been working nice (padlock etc) for some time, just trying Devious Green (Updated) theme, also https://addons.mozilla.org/en-US/firefox/addon/devious-green-updated/?src=cb-dl-created Have you got PM in WSA's protected applications etc?
You'll just want to add it manually to the Protected Applications list under the Identity & Privacy feature, which lets you add any application to be protected.