I've noticed that the new stable sea of nodes layout is not deterministic. Here are the steps to reproduce this:

1. Open IGV
2. Open reproduce.xml
3. Open the (only) graph After Iter GVN
4. Search for node 107 ParsePredicate and extract it
5. Expand neighboring nodes 116 IfTrue and 108 IfFlase
6. Switch to the stable sea of nodes layout
7. Expand 61 IfTrue

Repeating these steps I sometimes get layout1.png and sometimes layout2.png. This randomness seems to be odd and is probably not expected. We should make sure that the algorithm is deterministic and always produces the same layout for the same set of nodes.