I had LO installed by Xubuntu 16.04-6, and I had scroll bars. The other day I did a dist-upgrade to Xubuntu 18.04, resulting in LO 6.1.something, and all scroll bars disappeared from LO, even in floating toolbars (I keep them off to the right). After searching here and all over the net for a solution, I found the suggestion to add Vertical Scroll Bar and Horizontal Scroll Bar to the File > menu. I did so, but they do not work; I can click on the menu entry and nothing happens, not even a check mark next to the menu item.
After my complete failure to find a solution I uninstalled all the LO packages from the Ubuntu repositories and downloaded 184.108.40.206 from here. After installing it I find that all the scroll bars are still missing everywhere. The scroll wheel on the mouse works, and I can PgDn and PgUp, but those are my only navigation options.
I hope someone can come up with a solution. All suggestions gratefully received!