Never modify default window size option
TBB starts with a default window size rather than full screen. Many users (like myself) accidentally change/resize it and of course this can be bad for fingerprinting.
There should be an option (in Torbutton?) like "Never change the default screen size" for users who want to make sure they never accidentally change the default screen size (and those who want to be able to change it can just untick/leave the option off).