Any way to sort two layers together?

I have a sorted mark_bar() and would like to add a layer of mark_tick or top of this, while preserving the sorted order.

This sorting works:

from vega_datasets import data
df = data.movies()
df['WW_Margin'] = (df['Worldwide_Gross'] - df['Production_Budget']) / 1e6
  
lower_box = 'q1(WW_Margin):Q'
upper_box = 'q3(WW_Margin):Q'

bar_plot = alt.Chart(df).mark_bar(size=5.0).encode(
    alt.X('Major_Genre:O',
#          sort=alt.SortField(field='WW_Margin', op='median', 
#                             order='descending')
         ),
    y=lower_box,
    y2=upper_box,
)

median_tick = bar_plot.mark_tick(
    color='white',
    size=5.0
).encode(
    y='median(WW_Margin):Q',
)

bar_plot

But when I add a mark_tick layer, the sorting or the bars is gone, and it reverts to alphabetical sorting.

from vega_datasets import data
df = data.movies()
df['WW_Margin'] = (df['Worldwide_Gross'] - df['Production_Budget']) / 1e6
  
lower_box = 'q1(WW_Margin):Q'
upper_box = 'q3(WW_Margin):Q'

bar_plot = alt.Chart(df).mark_bar(size=5.0).encode(
    alt.X('Major_Genre:O',
          sort=alt.SortField(field='WW_Margin', op='median', 
                             order='descending')
         ),
    y=lower_box,
    y2=upper_box,
)

median_tick = bar_plot.mark_tick(
    color='white',
    size=5.0
).encode(
    y='median(WW_Margin):Q',
)

bar_plot + median_tick #note below that sorting is gone

This is quite possibly related to #698 which in turn refers to a Vega-lite issue(vega/vega-lite#2177). Will this get resolved when a newer version of Vega-lite is incorporated into Altair? Thanks much.

[jakevdp]

The order of the axis and the order in which the points are connected are distinct concepts. If you want to change the order in which the points are connected, you can use the order channel. Details in the docs here: https://altair-viz.github.io/user_guide/encoding.html#ordering-marks

[jakevdp]

Also, ordering of axis for layered charts based on different datasets is still not supported (open the javascript console and you’ll see the relevant warnings output by Vega-Lite). You’ll need to source both charts from the same dataset if you want the orders to be propagated to the layered chart.