private void deleteGraphEdge(Edge edge) {
// make sure we aren't deleting a null edge
assert (edge != null);
assert (edge.type == Edge.Type.GRAPH_EDGE);
// deselect if necessary
if (edge == selectedItem) selectEdge(null);
queryGraph.removeEdge(edge.getQueryEdge());
graphEdges.remove(edge);
// signal deletion
fireEvent(edge, GRAPH_CHANGED);
}
