Can't draw spike line across subplots with make_subplots in 4.0.0

After upgrading to plotly 4.0.0, I can't see how to create a spike line across shared axes created with make_subplots.

Previously I was using code like this:

from plotly.tools import make_subplots
from plotly.io import write_html

fig = make_subplots(rows=4, cols=1, shared_xaxes=True)
x_vals = list(range(10))
y_vals = [x**2 for x in x_vals]
fig.add_scatter(x=x_vals, y=y_vals, row=1, col=1)
fig.add_scatter(x=x_vals, y=y_vals, row=2, col=1)
fig.add_scatter(x=x_vals, y=y_vals, row=3, col=1)
fig.add_scatter(x=x_vals, y=y_vals, row=4, col=1)

fig.update_xaxes(spikemode='across+marker')

write_html(fig, 'out.html', auto_open=True)

The resulting figure showed spike lines across axes because only one x axis was created:

But in 4.0, multiple x axes are created so the spike line no longer draws across all subplots:

Is there any way around this? Thanks!

Inizia con la riproduzione Python fornita usando make_subplots, shared_xaxes e fig.update_xaxes(spikemode='across+marker'). Confronta la configurazione generata degli assi dei subplot in Plotly 4.0 con il comportamento precedente di un singolo asse. Il lavoro è completo quando viene identificato un modo supportato per estendere la linea spike su tutti i subplot condivisi, oppure quando vengono documentati tale limite e il relativo workaround.