Setting a default style affects loaded scores, not just new ones
Windows 7, GIT commit: 4554f23
1) save attached style file BigArialTitle.mss in your Styles folder
2) Edit / Preferences / Score
3) Set "Style" to the style file you just saved
4) Open any score
Result: title is big and Arial
It seems the style settings made in Edit / Preferences / Score *override* whatever is in any subsequently loaded score, rather than simply setting the defaults for new scores as I assume was the intended behavior.
I believe this also leads to other problems with the chordlist element down the road that can lead to crashes (see #23950: Crash after closing score if loading style that defines chord id). It's possible fixing the basic default style issue will also fix that crash.
The BigArialTitle.mss file was generated by creating a new score, going to Style / Text / Title, and setting the font to Arial 64pt, then Style / Save Style. So it contains all default settings (as of 12/17/2013) except this.