add option to add "select" mode on any figure (specifically, Heatmap)

It doesn't seem possible to add a "select" dragmode to a figure with a go.Heatmap object. You can specify the starting dragmode as "select", in which case you can immediately drag and select. But if I wanted to pan, I can't choose to select afterwards. I cannot add it to the modebar. I would like to be able to do this so I can select a region of interest on my heatmap, and setup a callback to set this region of interest in my code. I don't care about actually selecting the points in the heatmap, just the bounds of the selection box.

My workaround to this is to add a go.Scatter to my figure:

layout =  go.Layout(
        showlegend=False,
        autosize=False,
        xaxis=dict(
            showgrid=False,
            zeroline=False,
            visible=False,
            range=[0, images.shape[2] - 1],
        ),
        yaxis=dict(
            showgrid=False,
            zeroline=False,
            visible=False,
            range=[images.shape[1] - 1, 0],
            scaleanchor="x",
            scaleratio=1,
        ),
        dragmode="zoom",
        modebar=go.layout.Modebar(remove=["lasso"]),
    )

heat = go.FigureWidget(
    data=[
        go.Scatter(
            x=[0],
            y=[0],
        ),
        go.Heatmap(z=current_image, colorscale="Viridis"),
    ],
    layout=layout,
)

This works, but is kind of silly...

Start with the go.FigureWidget example, focusing on layout.dragmode, modebar options, and the go.Heatmap interaction described in the issue. Check how selection callbacks and selection bounds are exposed when the figure contains only a Heatmap. Done means switching between pan or zoom and select works through the modebar without adding a dummy go.Scatter.