I am linking 4 graphs together in Dygraphs. It all works fine. When I mouse over one graph, I see the readout for all 4 graphs which is what I want.

However, when I zoom in to one graph, they all zoom in, but the legends are not displaying except for the one I am hovering over.

Also, when I zoom back out (double click ) it only shows one legend at a time. And it is the graph that I had zoomed-in on, regardless of where my mouse is now.

I am using a double click plugin as shown.

const doubleClickZoomOutPlugin = {
    activate: function (g) {
        // Save the initial y-axis range for later.
        const initialValueRange = g.getOption('valueRange');
        return {
            dblclick: e => {
                e.dygraph.updateOptions({
                    dateWindow: null,  // zoom all the way out
                    valueRange: initialValueRange  // zoom to a specific y-axis range.
                });
                e.preventDefault();  // prevent the default zoom out action.
            }
        }
    }
}

How can I adjust this plugin this to show all 4 legends whenever I mouse over one of them. In other words, to reset the legend draw functionality.

Thanks!