Ok, for Arch it`s fixed. What about other distros? Linux Mint 17.3 x64 "Rosa", Enpass 5.2.1 installed from deb-repository http://repo.sinew.in/ , Enpass extension for Firefox from Mozilla repository - I see same problem: when clicking on Enpas extension button, nothing is happens (Enpass is sitting in tray at that time).
lsof -i:10391
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
firefox 3719 user 77u IPv4 83147 0t0 TCP localhost:44810->localhost:10391 (ESTABLISHED)
Enpass 4784 user 16u IPv4 66865 0t0 TCP localhost:10391 (LISTEN)
Enpass 4784 user 26u IPv4 83148 0t0 TCP localhost:10391->localhost:44813 (ESTABLISHED)