The body of a commit message has a best practice guideline of being a maximum of 72 characters wide. Add a second line behind the commit message textfield to indicate the 72 character width.
Requires the application of these patches: http://groups.google.com/group/gitx/browse_thread/thread/41562b79cd00b6ca See also: http://groups.google.com/group/gitx/browse_thread/thread/9740cf9d9e2cc52c/3c5870970daae519
