selectedNodeData does not contain pre-selected nodes

[michael-hlavacek]

Description

When using the selected attribute of nodes, the selected nodes are not contained in the selectedNodeData attribute after adding more nodes to the selection via ctrl + click.

Steps/Code to Reproduce

import dash
import dash_cytoscape as cyto
import dash_html_components as html
from dash.dependencies import Output, Input

app = dash.Dash(__name__)

app.layout = html.Div([
    cyto.Cytoscape(
        elements=[
            {
                'data': {
                    'id': 1,
                    'label': 1
                },
                'selected': True
            },
            {
                'data': {
                    'id': 2,
                    'label': 2
                }
            }
        ],
        id='graph'
    ),
    html.Pre(id='node-data')
])

@app.callback(Output('node-data', 'children'), [Input('graph', 'selectedNodeData')])
def print_selected_node_data(selected_node_data):
    return str(selected_node_data)

if __name__ == "__main__":
    app.run_server(port=8051, debug=True)

After opening the page, node 1 is selected by default. Ctrl + click on node 2.

Expected Results

Ctrl + click on node 2 -> selectedNodeData contains [{'id': '1', 'label': 1}, {'id': '2', 'label': 2}].

Actual Results

After opening the page, node 1 is selected by default. Ctrl + click on node 2 -> selectedNodeData contains just [{'id': '2', 'label': 2}].

Versions

Dash 1.8.0 Dash Core Components 1.0.2 Dash HTML Components 1.7.0 Dash Renderer 1.2.3 Dash HTML Components 0.1.1