gutter width not changed on changing font face and size

[gotoh]

When I change the font or font size, the text in the diff display also changes accordingly, but the width of the gutter for the line number column and the "+"/"-" indicator remains unchanged. As a result, increasing the font size can cause the line numbers to become too large to display completely. The same thing happens when I change the font.

Restarting the application will fix it, though.

Size=13

Size=16

[love-linger]

Fixed.