Fillcolor not working for contours_type="constraint"

[not_organic]

Hello,

I am not able to use the fillcolor argument to plotly.graph_objects.Contour when the contours_type is set to “constraint”. Am I missing something or is this a bug?

import plotly.graph_objects as go
import plotly.express as px
import numpy as np

H, _, __ = np.histogram2d(*np.random.normal(size=(10000, 2)).T, bins=100)
i = 0

trace = go.Contour(
    x=np.linspace(0, 1, 100),
    y=np.linspace(0, 1, 100),
    z=H,
    contours_type="constraint",
    contours_operation="=",
    contours_value=0,
    fillcolor="#000000",
    line_color=px.colors.qualitative.Plotly[i],
)

fig = go.Figure(
    data=[trace],
    layout={
        "width": 800,
        "height": 800,
    },
)

fig.show()