Adding a stream.Selection1D doesn’t work on the hv.Graph. It works with the graph.nodes but only if displaying graph.nodes*graph.edgepath

```
# Declare abstract edges
N = 8
node_indices = np.arange(N, dtype=np.int32)
source = np.zeros(N, dtype=np.int32)
target = node_indices
simple_graph = hv.Graph(((source, target),))
simple_graph
```

Adding selection1D with source simple_graph doesn’t work so I used source to the simple_graph.nodes

```
s1d = hv.streams.Selection1D(source=simple_graph.nodes)
def select_index(index):
print('Selecting index: ',index)
s1d.add_subscriber(select_index)
```

The above still doesn’t do any callbacks.

However if I display graph nodes overlayed with graph edgepaths it works

```
simple_graph.edgepaths*simple_graph.nodes
```

Now the events for selection works but the graph selection features and styling are gone.

What gives?