Help says to switch off the annoying pop up help tips at:
Tools - Options’ - LibreOffice - General’
In my instance it is off; I also tried to switch off anything to do with autocorrect, other tips, etc, but while typing the yellow box keeps on popping up.
Also, despite auto correct not enabled, words are auto completed, which is extremely annoying as 99% of the time the completion is wrong.
This is for V 188.8.131.52
on Win 8
I have also had a continuous problem with Spelling suddenly stop working (reported long ago as Bug 92150). I need to continuously fix this by deleting the user profile at \LibreOffice\4\user. It then works for a while, but somehow Spell Check gets lost again.