Why LibreOffice 5.2 is not part of the Unity bar in Ubuntu Linux?
Same issue, Unity context menu isn’t working with 5.2
I might be misunderstanding the question, but I had issues with LibO 5.2 after upgrade … both to 16.04 LTS (from 14.04) and up to the most recent LibO (I am currently running Version: 5.2.0.4; Build ID: 1:5.2.0~rc4-0ubuntu1~xenial).
There is a similar issue raised on AskUbuntu: it appears that libreoffice-gnome is not automatically installed. You can install it from the command line, or get it from Synaptic (which is what I did:
Note that in the screenshot, libreoffice-gtk and libreoffice-gtk2 are also shown as installed: when you mark libreoffice-gnome, the two “gtk” packages get automatically marked as well. Since installing, my file operations on LibO 5.2 have gone back to “normal” for me (was getting a terrible interface before).