review plot recipe for ORBIT with subset array

[mforets]

ivp, _ = harmonic_oscillator()

A = state_matrix(ivp)
X0 = initial_state(ivp)
prob = @ivp(x' = A*x, x(0) ∈ X0)
sol = solve(prob, alg=ORBIT(δ=0.1), NSTEPS=10);

# with gr the plot is empty

plotly()

plot(sol[1:1:end], vars=(0, 1))
UndefRefError: access to undefined reference

Stacktrace:
 [1] getindex at ./array.jl:809 [inlined]
 [2] iterate at ./array.jl:785 [inlined] (repeats 2 times)
 [3] show_json(::JSON.Writer.PrettyContext{Base.GenericIOBuffer{Array{UInt8,1}}}, ::JSON.Serializations.StandardSerialization, ::Array{Any,1}) at /home/mforets/.julia/packages/JSON/3rsiS/src/Writer.jl:292
 [4] #show_json#3 at /home/mforets/.julia/packages/JSON/3rsiS/src/Writer.jl:325 [inlined]
 [5] print(::Base.GenericIOBuffer{Array{UInt8,1}}, ::Array{Any,1}, ::Int64) at /home/mforets/.julia/packages/JSON/3rsiS/src/Writer.jl:347
 [6] sprint(::Function, ::Array{Any,1}, ::Vararg{Any,N} where N; context::Nothing, sizehint::Int64) at ./strings/io.jl:105
 [7] sprint at ./strings/io.jl:101 [inlined]
 [8] json at /home/mforets/.julia/packages/JSON/3rsiS/src/Writer.jl:366 [inlined]
 [9] plotly_series_json at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/plotly.jl:879 [inlined]
 [10] plotly_html_body(::Plots.Plot{Plots.PlotlyBackend}, ::Nothing) at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/plotly.jl:927
 [11] plotly_html_body at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/plotly.jl:902 [inlined]
 [12] html_body at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/plotly.jl:884 [inlined]
 [13] standalone_html(::Plots.Plot{Plots.PlotlyBackend}; title::String) at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/web.jl:7
 [14] standalone_html(::Plots.Plot{Plots.PlotlyBackend}) at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/web.jl:7
 [15] _show at /home/mforets/.julia/packages/Plots/SjqWU/src/backends/plotly.jl:965 [inlined]
 [16] show(::Base.GenericIOBuffer{Array{UInt8,1}}, ::MIME{Symbol("text/html")}, ::Plots.Plot{Plots.PlotlyBackend}) at /home/mforets/.julia/packages/Plots/SjqWU/src/output.jl:215
 [17] sprint(::Function, ::MIME{Symbol("text/html")}, ::Vararg{Any,N} where N; context::Nothing, sizehint::Int64) at ./strings/io.jl:105
 [18] sprint at ./strings/io.jl:101 [inlined]
 [19] _ijulia_display_dict(::Plots.Plot{Plots.PlotlyBackend}) at /home/mforets/.julia/packages/Plots/SjqWU/src/ijulia.jl:56
 [20] display_dict(::Plots.Plot{Plots.PlotlyBackend}) at /home/mforets/.julia/packages/Plots/SjqWU/src/init.jl:77
 [21] #invokelatest#1 at ./essentials.jl:710 [inlined]
 [22] invokelatest at ./essentials.jl:709 [inlined]
 [23] execute_request(::ZMQ.Socket, ::IJulia.Msg) at /home/mforets/.julia/packages/IJulia/e8kqU/src/execute_request.jl:112
 [24] #invokelatest#1 at ./essentials.jl:710 [inlined]
 [25] invokelatest at ./essentials.jl:709 [inlined]
 [26] eventloop(::ZMQ.Socket) at /home/mforets/.julia/packages/IJulia/e8kqU/src/eventloop.jl:8
 [27] (::IJulia.var"#15#18")() at ./task.jl:356