Legacy plot titles don't change when they should on rerender

[jnumainville]

Legacy plot titles don't change when they should.
In the below example, the title never changes from the initial sym

import deephaven.plot.express as dx
from deephaven.plot.figure import Figure

stocks = dx.data.stocks()
syms = stocks.view("Sym").select_distinct("Sym")

@ui.component
def plot_with_title():
    sym, set_sym = ui.use_state("LIZARD")
    picker = ui.picker(syms, selected_key=sym, on_change=set_sym)

    plot_line = (
        Figure()
        .plot_xy(series_name="Price", t=stocks, x="Timestamp", y="Price")
        .figure_title(f"Price of {sym}")
        .show()
    )
    return [picker, plot_line]

test = plot_with_title()

[mattrunyon]

A (not great) workaround is to add a wrapper with key=title. Stan ran into this same issue, but I hadn't opened a ticket for it yet.

The issue is actually in @deephaven/chart where the Chart component does not respond to all changes in the plotly layout. Since the title is in the layout, but has no special handling, it doesn't respond to changes. I think axis labels have the same issue.

So the component isn't re-mounted on the client which is why adding a key prop to a wrapper is a workaround. It forces React to re-mount the component