js_on_click not working for Button inside FloatPanel

[MarcSkovMadsen]

panel==1.2.1

In https://discourse.holoviz.org/t/copy-to-clipboard-js-callback-on-a-floatpanel-not-working/5831 Monodera reports that he cannot get copy to clipboard working for a Button inside the FloatPanel.

I've reduced the example to

import panel as pn


def copy_to_clipboard_in_floatpanel():
    copy_source_button = pn.widgets.Button(
        name="✂ Copy Source Value", button_type="success"
    )
    copy_source_code = "console.log('allo')"
    copy_source_button.js_on_click(
        code=copy_source_code
    )
    return pn.layout.FloatPanel(copy_source_button, name="Float")
    # return pn.Column(copy_source_button, )


copy_to_clipboard_in_floatpanel().servable()

If you click the button, I would expect allo to be printed in the browser console. But it is not.

If you place the copy_source_button inside a Column (commented out code line), it works.