Can not generate a multiline textbox on XUL dialog (Thunderbird 68.5.0)

Question

I can not understand in my writing Thunderbird addon that a textbox is not generated as multiline against my intension.

Could you tell me the reason or point out the wrong code? Or could you tell me any good addons using some dialogs with some multiline textbox elements for TB version 68 or later?

enter image description here

The sample code is as follows:

<?xml version="1.0"?>
<?xml-stylesheet href="chrome://global/skin/global.css" type="text/css"?>

<dialog id="sample" title="multiline textbox"
        xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">

<textbox multiline="true" rows="3"
         value="This is some text that could wrap onto multiple lines."/>

</dialog>

// Launcher
        window.open(  // or window.openDialog
            "chrome://myaddon/content/sample.xul",
            "sampleDlg",
            "resizable,chrome,modal,titlebar,centerscreen");

Thank you in advance.

Answer 1

<textbox multiline="true"> is removed. Use <html:textarea> instead.

Reference: https://developer.thunderbird.net/add-ons/updating/tb68/changes