[BUTTON DISAPPEARANCE] I am updating TaskviewLayout, but problem occurred

Problem is that button disappears if restarting! Please, advise me.
I used legacy API because of being difficult to port my addon to Lightning.

XUL file is as below.
<?xml version=“1.0”?>
<?xml-stylesheet href=“taskviewlayout.css” type=“text/css”?>
<overlay id=“ltnToolbarOverlay” xmlns=“http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul”>
<script type=“text/javascript”
src=“taskviewlayout.js”/>
<script type=“text/javascript”
src=“tv4.js”/>
<toolbarpalette id=“TaskToolbarPalette”>
<toolbarbutton id= “taskviewlayout” tooltiptext=“Taskview Layout” class=“toolbarbutton-1 chromeclass-toolbar-additonal” label=" Taskview layout" type=“menu-button”>
<menupopup>
<menuitem id=“menuitem1” label=“View to put task view up” onclick=“tv1();”/>
<menuitem id=“menuitem2” label=“View to put task view neutrally” onclick=“tv2();”/>
<menuitem id=“menuitem3” label=“View to put task view vertically” onclick=“tv3();”/>
</menupopup>
</toolbarbutton>
</toolbarpalette>
</overlay>

Script file is as below.
function tv1() {
var layoutContainer = document.getElementById(‘calendar-task-details-container’);
var layoutABox = window.document.getElementById(‘task-addition-box’);
window.document.getElementById(‘calendar-task-box’).insertBefore(layoutContainer, layoutABox);
document.getElementById(‘calendarDisplayDeck’).style.flex = ‘1’;
};

function tv2() {
var layoutContainer = document.getElementById(‘calendar-task-details-container’);
window.document.getElementById(‘calendar-task-box’).appendChild(layoutContainer);
document.getElementById(‘calendarDisplayDeck’).style.flex = ‘1’;
};

function tv3() {
var layoutContainer = document.getElementById(‘calendar-task-details-container’);
document.getElementById(‘calendarDisplayDeck’).style.flex = ‘0 2 0’;
document.getElementById(‘calendarContent’).appendChild(layoutContainer);
};

Sincerely.

Sungho Hwang.

It is stable in 71.0 beta version.
So, I changed strict min version to 71.0 in manifest.json.
Soon, version 55.6 is updated for Thunderbird 71.0 beta.

TaskviewLayout 55.6 was released and has been stable on Thunderbird 71.0, 72.0b1, 72.0b2. I think that the functionality of TaskviewLayout is good. I ask for your interest.

TaskviewLayout was updated as version 56.5 whose functionality was completed.

Taskview can be resizable on horizontal and vertical states,
and Taskview modes are not changing if clicking other tabs.

TaskviewLayout is working with over Thunderbird 71.0.

From Sungho Hwang.