Troubleshooting / Bugs: Rendering problem with line number margin

Small rendering problem when the line number margin dynamically expands or contracts.

Steps to reproduce:

1. Open a new document (or one that has less than 100 lines)
2. Hold enter until you get to 99 lines
3. Press enter one more time
4. The margin expands correctly for lines 99 and 100, but not for any lines above it
5. Delete line 100
6. The margin contracts correctly for line 99, but not for any lines above it

[click here for a picture]

Note: when you change lines or scroll (or anything else causing a repaint) the other lines are rendered correctly.

Fixed