I had this problem, and it was definitely a theme issue.
https://askubuntu.com/a/1372318 may be helpful in setting a theme just for libreoffice, it you're using GTK themes. (Basically, override the GTK_THEME variable in the .desktop file). I haven't tried it myself since I just switched to a different theme.
I had this problem, and it was definitely a theme issue.
https://askubuntu.com/a/1372318 may be helpful in setting a theme just for libreoffice, it you're using GTK themes. (Basically, override the GTK_THEME variable in the .desktop file). I haven't tried it myself since I just switched to a different theme.