toggleHover not showing up in modebar

I am working on a plot that has four subplots, with multiple traces on each. Plotly is a great solution for me because we have lots of data to show and having tooltips to call out specific data points is very useful using x unified hovermode. However, with so many traces the tooltip can get rather large; sometimes I want to be able to turn off tooltips using a button.

I was able to work something out using the updatemenus option in the layout a la:

    updatemenus=[
        dict(
            type = "dropdown",
            direction = "down",
            buttons=list([
                dict(
                    args=["hovermode", "x unified" ],
                    label="On",
                    method="relayout"
                ),
                dict(
                    args=["hovermode", False ],
                    label="Off",
                    method="relayout"
                ),
            ]),
            pad={"r": 10, "t": 10},
            showactive=True,
            x=1.05,
            xanchor="right",
            y=1.07,
            yanchor="top"
        ),
    ]

However, the buttons are rather large and don’t fit well, and I’d rather have a toggle button in the modebar as a cleaner solution.

It seems like this would be trivial to do in js, but I cannot get anything to work in python. I can see from the docs that there this a default toggleHover button available to the modebar config, but I cannot get it to show up. Does anyone know why it may not be showing up?