Browsers obviously all have the ability to search across the web, but they also have a Find Text tool (usually Ctrl+F) to find text in the viewed page. That would be very convenient for EndNote, but if that functionality is present, I can’t find it.
I use Endnote for extensive note taking for important references and tagging quotable quotes. It’s a research tool, not just a bibliography organizer. When I go looking for some text string in the notes field within a lengthy record, it can be very tedious.
Browsers have this function, text editors do too. Could EndNote?