I installed the keepass2 with all it's dependencies like mono-common from the ubuntu official repo and the xul-ext-keefox from the ppa in the ubuntu 17.10, and
the keefox extension from the firefox extensions site, when i started the keepass2 and keefox thy show me a code to copy to the keefox and i did it, but still keefox is not working and show me the install keefox, options and help menu.
when i click on install keefox the firefox open a page chrome://keefox/content/install_mono.xul and ask me to install the mono-common, keepass2 and to copy the
KeePassRPC.plgx to the /usr/lib/keepass2/Plugins that i already did.
The only thing is in this page Customisation instructions, to set the installtion paths for the keepass and Mono in the KeeFox -> Options -> Keepass.
The problem is the keepass didn't have this otpions, this is the options window
image:
https://ibb.co/cTrR36

i'm using keepassx (no mono dependencies), and it comes with automatic pasting (via hotkey) based on URL.

wouldn't that be sufficient as a working alternative?

Thanks for reply after searching and trying the keepassx autotype i find how to use it.