Updated Libre from 5.1 to 5.4.2.2. Lost icons. When i go to Tools - Options - View, Libre shows a fatal error.
Screenshots below.
(Edit: activated screenshots -AK)
Hi…I had the exact same issue…I’ve got a workaround if your interested…if installed, uninstall libreoffice-gnome, libreoffice-gtk, libreoffice-gtk2 and libreoffice-gtk3. Then launch writer, that time it will look really ugly and old school…under settings/view choose the icons you want to use, then close writer. Now reinstall libreoffice-gtk3. It should work, worked for me 
@plus
dom
I agree. This still holds true in 2020 on LibreOffice 6.4
This still holds true today. libreoffice-gtk, libreoffice-gtk2 and libreoffice-gtk3 are imperative for your theme integration.
Wish I would have stumbled on this post earlier.
Remember that gtk and gtk2 are deprecated in favour of gtk3 (this is not a LO requirement but GTK+ evolution). The bad experience also means the themes have not been updated to follow GTK+. Consequently, either drop non LO-endorsed themes (many of them if not all are user contributions) or carefully choose themes compliant with latest GTK+ version (this is not easy because many theme developers take for granted that GTK+ API never changes).