I am not using Virtualbox.
The tooltip issue is a known issue in Cinnamon.
The libreoffice menu issue seems to be specific to Virtualbox. It looks like it's not able to render Cinnamon well enough.
Installed the application for electronic identification (absolutely vital for us in Sweden) running as a plug-in in Google Chrome. It seems to work.
There is still a menu problem in LibreOffice:
When pointing at a update in the Update manager the same message appears in the upper left corner of the screen: