Makie realtime plot draws line from start datapoint after some time - BUG

General Usage
1

This is code for a realtime updating Makie line plot. It is setup to let you pan the chart on click.

If you let it proceed to about +3 days from the start data point it draws a straight line from the first data point to the current and pan performance significantly drops.

Is this an issue with the DateTime axis or something deeper with Makie?

using Dates

using GLMakie
GLMakie.activate!()
Makie.inline!(false)  # Probably unnecessary?

using Observables


function register_mouse_handlers(fig, ax, plot)
    let
        # Remove the rectangle zoom on left-click drag.
        deregister_interaction!(ax, :rectanglezoom)

        mouseevents = addmouseevents!(fig.scene)

        global pos
        global xmin
        global xmax
        global ymin
        global ymax
        global was_inside_plot = false

        onmouseleftdrag(mouseevents) do event
            if was_inside_plot
                px_delta = event.px - pos

                scale = extrema(ax.scene.px_area[])

                dx = px_delta[1] * (xmax - xmin) / scale[2][1]
                dy = -px_delta[2] * (ymax - ymin) / scale[2][2]

                # Update the axis limits to achieve panning
                xlims!(ax, xmin - dx, xmax - dx)
                ylims!(ax, ymin + dy, ymax + dy)
            end
        end

        onmouseleftdragstart(mouseevents) do event
            global was_inside_plot = is_mouseinside(plot)
            global pos = event.px

            limits = extrema(ax.finallimits[])
            global xmin, xmax = limits[1][1], limits[2][1]
            global ymin, ymax = limits[1][2], limits[2][2]
        end

        onmouseleftdragstop(mouseevents) do event
            global was_inside_plot = false
        end
    end
end


fig = Figure()

fig[1, 1] = chartgrid = GridLayout(tellwidth=false)

import PlotUtils: optimize_datetime_ticks

function get_timestamp_delta(timestamps)
    return Dates.value.(timestamps) .- Dates.value(timestamps[1])
end

struct DateTimeTicks
    t0::Dates.DateTime
end

function Makie.get_ticks(t::DateTimeTicks, any_scale, ::Makie.Automatic, vmin, vmax)
    dateticks, dateticklabels = optimize_datetime_ticks(
        Dates.value(Dates.DateTime(Dates.Millisecond(Int64(floor(vmin))) + t.t0)),
        Dates.value(Dates.DateTime(Dates.Millisecond(Int64(ceil(vmax))) + t.t0)),
    )
    return dateticks .- Dates.value(t.t0), dateticklabels
end

timestamps = collect(Dates.now():Second(1):Dates.now())
t0 = timestamps[1]

timestamps = Observable(get_timestamp_delta(timestamps))
y = Observable([0.0])
ax = Axis(chartgrid[2, 1], xticks=DateTimeTicks(t0))
lineplot = lines!(ax, timestamps, y)

# Pan functionality
register_mouse_handlers(fig, ax, lineplot)

xlims!(ax, Dates.value(Millisecond(Minute(0))), Dates.value(Millisecond(Minute(60 * 12))))
ylims!(ax, -100, 100)

dt = t0
tm = Timer((timer) -> begin
        for _ in 1:10000
            push!(timestamps[], Dates.value(dt) - Dates.value(t0))
            push!(y[], y[][end] + (rand() - 0.5))

            global dt += Millisecond(250)
        end

        notify(timestamps)
        notify(y)

        yield()
    end, 0.0, interval=0.25)

gl_screen = display(fig)

wait(gl_screen)