LO supports custom shortcuts for Bold, Italic, Underline and they all seem to work in English UI with Ctrl + B, I, U. With German UI, that is: Strg-Umschalt-F for Fett (Bold), Strg-Umschalt-K for Kursiv (italics) and Strg-Umschalt-U for Unterstrichen (underline). (Strg=CTRL, Umschalt=Shift) Seems that German shortcut for "Underline" has no effect (Strg+Umschalt+U), at least in Linux gtk3. Works for me in Windows. Was not there in 7.5, NOK in 24.2 and 25.8+.