Bare component returned by pn.bind cannot be updated by other callbacks

[TheoMathurin]

Panel 1.3.4 in a server

If a pn.bind returns a widget or a pane on its own, meaning not embedded in a layout, this component cannot be updated by other callbacks. It's the case for every parameter I've tried: value, disabled, loading, visible, enabled_dates...

Put it in a container and it's fine.

Here is a simple example:

import panel.widgets as pnw
import panel as pn


def bare_widget(value):
    return int_input1


def widget_in_row(value):
    return pn.Row(int_input2)


def callback(event):
    int_input1.visible = not int_input1.visible
    int_input2.visible = not int_input2.visible


dummy_checkbox = pnw.Checkbox(name='Dummy checkbox', value=True)
int_input1 = pnw.IntInput(value=10)
int_input2 = pnw.IntInput(value=10)
button = pnw.Button(name='Update widget', on_click=callback)

pn.Column(button,
          'Bare widget:',
          pn.bind(bare_widget, dummy_checkbox),
          'Widget in a Row:',
          pn.bind(widget_in_row, dummy_checkbox)
          ).servable()

No error is logged either in Python or Javascript.

[philippjfr]

There's two conflated issues here, the first is that your example reuses int_input twice, which sadly is not possible currently. Presumably you just did that to create an MRE though, the other issue is quite frustrating and I'll push a fix shortly.

[TheoMathurin]

Yes it was for the purpose of the MRE and I did not have this other limitation in mind. I will update it to use separate widget instances.