Click on "Tools - Bibliography Database" does nothing. The bibliography window does not appear. No error messages are shown.
I did ask about this in the #libreoffice channel of Freenode. The user @cloph_away suggested that the Base package was not installed, which actually was the reason. I only installed the Writer package (apt install libreoffice-writer) initially. Adding the Base package (apt install libreoffice-base) fixed the issue.
I was thinking that maybe it would be useful to add a notification message telling that Base is not installed in case when it is not installed.
Libreoffice was installed from https://launchpad.net/~libreoffice/+archive/ubuntu/libreoffice-5-1
Info from "About" view:
Build ID: 1:5.1.3~rc2-0ubuntu1~trusty1
CPU Threads: 4; OS Version: Linux 3.19; UI Render: default;
Locale: en-US (en_US.UTF-8)
It does something -- it call for installing the package via dbus/packagekit. However, IIRC Rene wanted it to fall back on just popping a messagebox.
FWIW, before asking for the package to be install via packagekit, it just crashed ...
> It does something -- it call for installing the package via dbus/packagekit
Well, I did not notice any activity, at least with Writer 18.104.22.168.
*** This bug has been marked as a duplicate of bug 54479 ***