When using the spreadsheet and changing the colour of the text, the system breaksdown. I am using Ubuntu 15.04 Mate.
Sounds strange. Maybe you should try this: https://wiki.documentfoundation.org/UserProfile#Resolving_corruption_in_the_user_profile Set to NEEDINFO. Change back to UNCONFIRMED, if the problem persists. Change to RESOLVED WORKSFORME, if the problem went away.