limits3.vl

{
    "height": 300,
    "config": {
        "legend": {
            "symbolLimit": 3,
            "unselectedOpacity": 0.1
        }
    },
    "mark": {
        "type": "point",
        "filled": true
    },
    "data": {
        "url": "https://vega.github.io/vega-lite/data/cars.json"
    },
    "width": 300,
    "$schema": "https://vega.github.io/schema/vega-lite/v4.json",
    "selection": {
        "sel": {
            "bind": {
                "legend": "dblclick"
            },
            "type": "multi",
            "on": "click",
            "fields": [
                "Origin"
            ]
        }
    },
    "encoding": {
        "color": {
            "field": "Origin",
            "type": "nominal"
        },
        "size": {
            "value": 20,
            "condition": {
                "value": 100,
                "selection": "sel"
            }
        },
        "shape": {
            "field": "Origin",
            "type": "nominal"
        },
        "x": {
            "field": "Horsepower",
            "type": "quantitative"
        },
        "y": {
            "field": "Miles_per_Gallon",
            "type": "quantitative"
        }
    }
}