IGV colors all nodes yellow because it thinks the "label" of the nodes have changed. But they should be the same.

To reproduce:
1) open `diff_bug.xml`
2) show the difference graph between the last two graphs: "Incremental Boxing Inline, Before beautify loops"
3) Now all nodes are colored yellow, which indicates that the properties have changed
4) click on any nodes und you see a "NEW_label" that is empty in the properties
5) if you open each graph separately you see that the label are the same for all nodes
6) after playing around for a while with IGV the bug goes away