itables widget height is incorrect

[mwouts]

Hi, thanks for maintaining Shiny!

I am the author of ITables, a Python wrapper for DataTables. The package provides a Jupyter Widget using AnyWidget, which works fine in Jupyter, but we see height calculation problems in Shiny, cf. mwouts/itables#360.

A MRE is here:

from shiny import App, ui
from shinywidgets import output_widget, render_widget
from itables.widget import ITable
from itables.sample_dfs import get_countries

app_ui = ui.page_fluid(
    ui.h1("Issue #360"),
    ui.p("The table height is not correct"),
    output_widget("my_table"),
    ui.p("More content, should not hide the table (but it does)"),
)

# Define server
def server(input, output, session):
    @render_widget
    def my_table():
        return ITable(df=get_countries(html=False))

# Create the Shiny app
app = App(app_ui, server)

The problem is that the table is hidden by the next UI component - we get to see only 6 rows when we should see 10, plus some extra information:

In the browser console I see this message:

Honestly I am not sure where the problem resides, within ITables, or AnyWidget, or Shiny, but I would appreciate help or advice on how to address it! Thank you.

[mwouts]

The above was with shiny==1.3.0, with shiny==1.4.0 I get the same problem but different messages in the browser console:

[cpsievert]

Hi @mwouts, thanks for reporting, and great to see itables using anywidget!

For the height issue, shinywidgets applies a bit of heuristics to get widgets to fill inside shiny's filling layout mechanism, and those heuristics obviously aren't right here. A workaround for now would be to ignore filling layout altogether. That is, change

output_widget("my_table")

to

output_widget("my_table", fillable = False)

We could have shinywidgets essentially mark itables as not compatible with filling, but ideally we'd have it "just work" with filling layout like plotly, altair, ipyleaflet, etc. Does itables have any notion of a table filling it's container element? FWIW, DT has this option for this sort of thing in R.

I'm not sure yet what's causing the t.state_change is undefined error, but it looks like a CSS string is being sent to a .create_view() method (which I think is expecting a WidgetModel object). Anyway, I'll have more of a look into why this might be happening, but if this CSS string looks familiar to you, any context you can provide would be helpful!

[mwouts]

Thank you @cpsievert ! That's a lot useful information... and will take me a bit to process 😄 I will have a look at how DT address the issue.

Re the state_change error the input seems to match what I expect for the style option, which is set at this line - most likely I am doing something incorrect there and it does not relate to shiny... I'll have a further look later on.