updatemenu button moves on 2nd click

Adding an updatemenu button to toggle the legend, the button shifts to the left on 2nd click under certain conditions.

https://user-images.githubusercontent.com/30958850/151654960-7786bdbb-3949-44a2-922a-a9e4cb045629.mp4

Minimal Example

import plotly.express as px
df = px.data.iris()
fig = px.scatter(df, x="sepal_width", y="sepal_length", color="species")

legend = dict(
    x=1, y=1, xanchor="right", yanchor="top", groupclick="toggleitem"
)

legend_toggle = dict(
    args=["showlegend", True],
    args2=["showlegend", False],
    label="Toggle legend",
    method="relayout",
)

fig.update_layout(
    legend=legend,
    updatemenus=[
        dict(type="buttons", buttons=[legend_toggle], showactive=True, x=1, y=1)
    ],
)

fig.update_xaxes(range=[0, 10])

fig.show()

首先运行最小 Python 示例，并在切换图例的同时重现 updatemenu 按钮在第二次点击时的移动。跟踪图例和 updatemenu 的布局处理，然后验证在所报告的条件下，重复切换不会改变按钮的位置。