How to add dropdown menu inside Makie recipe?

[sdanisch]

So it slightly awkward but works pretty well:

struct Solution
    data::Any
end

function Makie.plot(P::Type{<: AbstractPlot}, fig::Makie.FigurePosition, arg::Solution; axis = NamedTuple(), kwargs...)

    menu = Menu(fig, options = ["viridis", "heat", "blues"])

    funcs = [sqrt, x->x^2, sin, cos]

    menu2 = Menu(fig, options = zip(["Square Root", "Square", "Sine", "Cosine"], funcs))

    fig[1, 1] = vgrid!(
        Label(fig, "Colormap", width = nothing),
        menu,
        Label(fig, "Function", width = nothing),
        menu2;
        tellheight = false, width = 200)

    ax = Axis(fig[1, 2]; axis...)

    func = Node{Any}(funcs[1])

    ys = @lift($func.(arg.data))

    scat = plot!(ax, P, Attributes(color = ys), ys)

    cb = Colorbar(fig[1, 3], scat)

    on(menu.selection) do s
        scat.colormap = s
    end

    on(menu2.selection) do s
        func[] = s
        autolimits!(ax)
    end

    menu2.is_open = true

    return Makie.AxisPlot(ax, scat)
end

f = Figure();
lines(f[1, 1], Solution(0:0.3:10))
scatter(f[1, 2], Solution(0:0.3:10))
f |> display