Users of Spell Catcher X should be aware that this Safari beta has a bug that screws up auto-completion in a number of Apple apps, notably Mail. Instead of substituting the text for your abbreviation it will keep the first letter of the abbreviation and add the full text after it (various other oddities have also been reported). The bug is in the version of WebKit that the beta uses and can’t be worked around, in most cases anyway. More information at http://www.rainmakerinc.com/forums/index.php?showtopic=1357.

In short, if you rely on SC X, leave this beta well alone... If anyone knows whether the problem affects other autocompletion apps (TypeIt4Me, Typinator, etc), if would be great if you could you also post.