The special characters page that comes up in Librewriter under Version: 6.4.2.2 Build ID: 1:6.4.2-0ubuntu3 is next to unusable. Instead of a dozen or so rows of boxes with each character in its own box, there are only two rows of characters for a screen height of over 7 inches. The characters are now displayed in such a large font that they overlap. My Dell Vostro 3500 laptop has seen Libreoffice now for well over five years without this problem occurring. How do I fix it?
Which Ubuntu version and which desktop manager (GNOME, Mate, Cinnamon, Unity, KDE, Xfce,…) do you use? Could you provide a screenshot?
Can't confirm on Ubuntu 18.04 LTS (LibreOffice 6.4.3.2) and Ubuntu 20.04 (LibreOffice 6.4.3.2)
Did you check when running LibreOffice in **Safe Mode** (`Help -> Restart in Safe Mode..` and `Continue in Safe Mode` button), whether the problem still persists?
Restart in SAFE MODE and choose restore from backup. Open Special Character Menu, it should be normal sized and working. Close LO. Start in normal mode and it should work. Something got mangled.