Libreoffice Calc. When entering a formula in the formula bar tips pops up and obscures what you are typing. Tried disabling tips everywhere that I could see within the Options, including under the Expert section within which I searched for 'tip' and set all occurrences to FALSE. Pretty much makes Calc unusable and I really only use Fatdog infrequently for Libre Office (with Chrome running alongside that)
Might be because I'm using a Radeon based laptop, with the UI tweaks script in the /etc/profile.d folder set to have Libre use qt instead of gtk. Last time I used Libre calc in the 900 alpha/beta? I didn't notice that tip annoyance effect.