Nodes that are members of more than two sets fail

[leocrawford]

Instead of

    var data = [
                {"set":["A"],"name":"node_0"},
                {"set":["B"],"name":"node_1"},
                {"set":["B","A"],"name":"node_2"},
                {"set":["B","A"],"name":"node_3"}
                ]

We use

    var data = [
                {"set":["A"],"name":"node_0"},
                {"set":["B"],"name":"node_1"},
                {"set":["C"],"name":"node_2"},
                {"set":["B","A","C"],"name":"node_3"}
                ]

we Get

WARNING: area A,B,C not represented on screen

Experimenting, I can never get nodes that are member of more than two sets to work