Plotly_dark doesn't have draggable corners

The plotly_dark template disables the ability to rescale a plot by dragging on the corners.

How do I re-enable that feature?
(Thanks in advance)

import pandas as pd
import plotly.express as px

df = pd.DataFrame(dict(
x= [1,2,1, 2, 5, 5,6], #I’ve tried, 0, None, ‘’, etc.
y= [1,1,3, 4, None, 5,5],
color=[1,1,2, 2, 1, 1,1],
))

fig = px.line(df, x=‘x’, y=‘y’, color=‘color’, template=‘plotly_dark’)
fig.update_traces(connectgaps=False)
fig.show()