Altair selections don't work

Panel
1

Hi. So I’ve been trying to make a dashboard using Altair and Panel. One of the things I like most about Altair is it’s ability to interact between charts. As it’s shown [here](https://altair-viz.github.io/gallery/select_detail.html). However, I’ve not been able to figure out how to do that within panel. Can anyone help?

import altair as alt
import pandas as pd
import numpy as np
import panel as pn

np.random.seed(0)

n_objects = 20
n_times = 50

# Create one (x, y) pair of metadata per object
locations = pd.DataFrame({
    'id': range(n_objects),
    'x': np.random.randn(n_objects),
    'y': np.random.randn(n_objects)
})

# Create a 50-element time-series for each object
timeseries = pd.DataFrame(np.random.randn(n_times, n_objects).cumsum(0),
                          columns=locations['id'],
                          index=pd.RangeIndex(0, n_times, name='time'))

# Melt the wide-form timeseries into a long-form view
timeseries = timeseries.reset_index().melt('time')

# Merge the (x, y) metadata into the long-form view
timeseries['id'] = timeseries['id'].astype(int)  # make merge not complain
data = pd.merge(timeseries, locations, on='id')

# Data is prepared, now make a chart

selector = alt.selection_single(empty='all', fields=['id'])

base = alt.Chart(data).properties(
    width=250,
    height=250
).add_selection(selector)

points = base.mark_point(filled=True, size=200).encode(
    x='mean(x)',
    y='mean(y)',
    color=alt.condition(selector, 'id:O', alt.value('lightgray'), legend=None),
)

timeseries = base.mark_line().encode(
    x='time',
    y=alt.Y('value', scale=alt.Scale(domain=(-15, 15))),
    color=alt.Color('id:O', legend=None)
).transform_filter(
    selector
)

pn.extension('vega')

pn.Row(points , timeseries)