How to enable mouse click even on legend with repeat configuration

i am using repeat configuration and i could able to draw multiple series using this configuration. However when i try to set the params and try to bind with legend, it gives error duplicate signal. I am also using Spec configuration.

Appreciate your help in advance

{
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "data": {"url": "data/movies.json"},
  "repeat": {"layer": ["US Gross", "Worldwide Gross"]},
  "spec": {
    "mark": "line",
    "encoding": {
      "x": {"bin": true, "field": "IMDB Rating", "type": "quantitative"},
      "y": {
        "aggregate": "mean",
        "field": {"repeat": "layer"},
        "type": "quantitative",
        "title": "Mean of US and Worldwide Gross"
      },
      "color": {"datum": {"repeat": "layer"}, "type": "nominal"}
    }
  }
}

As noted in my comment above, there appears to be a known bug when combining "params" with a "repeat" view composition that uses "layer" in particular (GitHub link).

With this in mind, you'll need to refactor your specification to achieve the desired result. Here is a sample based on your provided example (example link). The key approach here is to use a "fold" transform to create new "key" and "value" fields from "US Gross" and "Worldwide Gross". With this change, the two lines can now be displayed within a single layer, and the interactive legend will now work.