Hover tooltips only show up on first element values

[hoxbro]

With the following code, the hover tooltip only shows up for the first element:

screenrecord-2023-11-09_15.42.21.mp4

import holoviews as hv
import pandas as pd
import panel as pn

hv.extension("bokeh")

color_dim = hv.dim("category").categorize(
    categories={"B": "red", "A": "blue", "C": "green"}, default="grey"
)
data = pd.DataFrame(
    {"x": range(5), "y": range(5), "category": ["A", "B", "A", "C", "B"]}
)


def inner(value):
    el = (
        hv.Dataset(data)
        .to(hv.Points, kdims=["x", "y"], groupby="category")
        .opts(tools=["hover"], size=10)
    )
    if value:
        el = el.get(value)
    el.opts(color=color_dim, show_legend=False, xlim=(-1, 6), ylim=(-1, 6))
    return el.overlay()


w1 = pn.widgets.MultiSelect(value=["A"], options=list("ABC"))
pn.Column(w1, hv.DynamicMap(inner, streams=[w1.param.value])).servable()

If I change the default value of the widget to A and B, those values show up.

[TheoMathurin]

Some exploration into the issue using this code:

import panel as pn
import holoviews as hv
pn.extension()


def make_plot_with_label(label):
    return hv.Scatter([1, 2, 3, 4], label=label).opts(title=label)


def make_plot_without_label(label):
    return hv.Scatter([1, 2, 3, 4], label='Scatter').opts(title=label)


hv.opts.defaults(hv.opts.Scatter(tools=['hover'], size=12))

scatter = hv.Scatter([4, 3, 2, 1])
dmap1 = hv.DynamicMap(make_plot_with_label, kdims=['label']).redim.values(label=['Scatter A', 'Scatter B'])
overlay1 = scatter * dmap1
dmap2 = hv.DynamicMap(make_plot_without_label, kdims=['label']).redim.values(label=['Scatter A', 'Scatter B'])
overlay2 = scatter * dmap2

pn.Column('## No hover tool on Scatter B',
          overlay1.opts(show_legend=False),
          '## It works if only one element',
          dmap1,
          '## It works if label does not change',
          overlay2.opts(show_legend=False)).servable()

As mentioned in the snippet, the issue seems to lie with changing element labels when there are more than one elements in the plot.