[BZ#774327] 3.16.3 : should scrool down if 1 file is juts 1 line larger than the other

Submitted by Toralf Förster

Description

for i in $(seq 1 41); do echo $i >> a; echo $i >> b; done; echo 42 >> b; meld a b

left is a yellow line, right are just the first 2 pixels of the green line are seen