I can't see any hint of the possible slowness issue noted above with all files in the biggest C++ project I have open, so I think its only likely to affect people with the kernal or chromium symbols open.
This is something I'd still like to look at - I think I could optimize the non-scope autocompletion a bit so it doesn't have to govthrough so many symbols (and sort those). The biggest danger is libraries like `glib` or `gtk` where all the symbols have the same prefix `g_` or `gtk_` and are possible candidates for the autocompletion popup.