Overflowing pane container

[droumis]

ALL software version info

panel 1.4.1

Description of expected behavior and the observed behavior

While trying to get a tabulator table to fit within widgetbox in a sidebar. I found that the table overflows the pane container. This is not specific to sidebar.

Complete, minimal, self-contained example code that reproduces the issue

import pandas as pd
import numpy as np
import panel as pn; pn.extension('tabulator')

vals = np.arange(100)
df = pd.DataFrame({f'column{l}':vals for l in np.arange(5)})

widget = pn.WidgetBox(
    pn.pane.Alert('Tabulator overflows pane container', alert_type='warning'),
    pn.widgets.Tabulator(df,
                         layout='fit_data_fill',
                         pagination='local',
                         page_size=10,
                        ),
    pn.pane.Alert('Tabulator overflows pane container', alert_type='warning'),
)

template = pn.template.FastGridTemplate(
    sidebar=[widget],
    main=[widget],
)
template.servable();

Stack traceback and/or browser JavaScript console output

Screenshots or screencasts of the bug in action

• I may be interested in making a pull request to address this

[droumis]

Same with Accordion

[droumis]

[ahuang11]

To get around this, I think you can set sizing_mode="stretch_width" on Tabulator

Tried manually adding width: calc(100% - 20px) and it seems to work too.