When drawing the commit message line, the given rect should not be used
for anything other than clipping. According to the comment, the code that
draws the line relies on the text view always drawing complete lines.
However, it also draws fragments, specifically when the insertion point
is flashing. By ignoring the given rect, not only is our line more accurate
in its positioning, but we also handle the case where the insertion point
is sitting on top of the line.
Since Git recommends to use 50 characters in the first line of a commit
message, this adds a vertical line to the commit message view to show where
the 50 char limit is.
[PB: This preference can be changed using a user default -- for now we don't
have a preference pane yet, so this is hidden.]
Kevin Ballard