node positions do not work with link value zero in Sankey

Hello,
I'm new to the plot.ly lib but I already discovered an issue.
If there is a node with:

• no links
• only links with the value of zero

the manual positioning doesn't work anymore except if you delete the relating coordinates of this node and keep the node in the list (see third example).

Below you can find a short testing code with the generated output.

working example

import plotly.graph_objects as go
data=go.Sankey(
    arrangement = "freeform",
    node = {
        "label": ["A", "B", "C", "D", "E", "F"],
        "x": [0.2, 0.1, 0.9, 0.7, 0.3, 0.9],
        "y": [0.1, 0.9, 0.2, 0.1, 0.9, 0.9],
        'pad':100},  # 10 Pixels 
    link = {
        "source": [0, 0, 1, 4, 4, 3, 3],
        "target": [1, 3, 4, 3, 5, 2, 5],
        "value": [3, 3, 5, 4, 10, 1, 7 ]})
fig_sankey = go.Figure(data=data)
fig_sankey.show()

node with only one link with value of zero

import plotly.graph_objects as go
data=go.Sankey(
    arrangement = "freeform",
    node = {
        "label": ["A", "B", "C", "D", "E", "F"],
        "x": [0.2, 0.1, 0.9, 0.7, 0.3, 0.9],
        "y": [0.1, 0.9, 0.2, 0.1, 0.9, 0.9],
        'pad':100},  # 10 Pixels 
    link = {
        "source": [0, 0, 1, 4, 4, 3, 3],
        "target": [1, 3, 4, 3, 5, 2, 5],
        "value": [3, 3, 5, 4, 10, 0, 7 ]})
fig_sankey = go.Figure(data=data)
fig_sankey.show()

kind of working again cause coordinates of C are deleted

import plotly.graph_objects as go
data=go.Sankey(
    arrangement = "freeform",
    node = {
        "label": ["A", "B", "C", "D", "E", "F"],
        "x": [0.2, 0.1, 0.7, 0.3, 0.9],
        "y": [0.1, 0.9, 0.1, 0.9, 0.9],
        'pad':100},  # 10 Pixels 
    link = {
        "source": [0, 0, 1, 4, 4, 3, 3],
        "target": [1, 3, 4, 3, 5, 2, 5],
        "value": [3, 3, 5, 4, 10, 0, 7 ]})
fig_sankey = go.Figure(data=data)
fig_sankey.show()

Comece executando os exemplos de Sankey em Python fornecidos e comparando o posicionamento livre quando um link tem valor zero. Rastreie o caminho de renderização do Sankey desde a definição da figura em Python até o componente que trata das posições dos nós. O trabalho estará concluído quando as coordenadas manuais continuarem efetivas para nós sem links ou com apenas links de valor zero, com um teste de regressão cobrindo ambos os casos.