Comment 1 for bug 1863282

Thanks for the report!

I was able to reproduce the missing menu bar in libreoffice on a kde neon 5.18.0 system if I installed libreoffice-kde and/or libreoffice-kde4 (libreoffice-kde depends on libreoffice-kde4). If either/both of these are installed, then you will not have a menu bar in libreoffice.

My guess is this is because your plasma version is 5 when you're installing libreoffice-kde4. In 19.10, we provide libreoffice-kde5 and I bet this would work but I can't test it because if you update your repos to point to eoan instead of bionic and go to install libreoffice-kde5, it will remove the neon-desktop. Also, since kde neon is based on Ubuntu LTS only, there is no 19.10 version to try.

So for now, I recommend installing libreoffice (do not install libreoffice-kde/libreoffice-kde4):

$ sudo apt install libreoffice

Yes, this does install libreoffice-gnome and libreoffice-gtk3, but that should not conflict with anything you are doing.

The next Ubuntu LTS is 20.04, due in April, and I would expect this issue to go away with libreoffice-kde5 in the kde neon image based on 20.04. So I'll leave this bug open until that is confirmed.