Comment 2 for bug 247820

This code is to handle the following situation: if you have the following rev graph:

3
|\
| 2.1.1
|/ \
2 |
| 1.1.1
|_/
1

If you select 1 and click on the link to 1.1.1, then it must also make 2.1.1 visible.

My code was not 100%, in that the loop should be stopping when it gets to the mainline. I have fixed this and reported bug.