Specific groups (methods) listed in the Outline window cannot be removed when they have been imported via network.

STEPS TO REPRODUCE IT:

1. $ cd src/utils/IdealGraphVisualizer
2. $ mvn install
3. $ sh igv.sh
4. $ java -XX:PrintIdealGraphLevel=3
5. In the "Outline" window group, select any group (e.g. "virtual void java.lang.Object.<init>()").
6. Go to File -> Remove selected graphs and groups
7. The selected group is not removed

WORKAROUND:

Save all groups into an XML file, remove all graphs and groups, open the XML file, and remove the desired groups (removing specific groups works as expected when they are imported from a file).

(Thanks to [~neliasso] for the original report).