The word "LibreOffice" isn't in the dictionary by default, and it's underlined as if misspelled.
This happens in both Writer and Calc, but I can't select more than one component in Bugzilla.
Could you please retry using LO 220.127.116.11? http://www.libreoffice.org/download/pre-releases/
Using 18.104.22.168 with german language and typing LibreOffice the word does not get underlined. Other test words I mistyped on purpose did get underlined.
22.214.171.124 in english also does not underline the word LibreOffice.
Seems this already was added somewhere on the way.