>>58
var undoPopup = document.getElementById("myUndoPopup");
if(!undoPopup){
undoPopup = document.createElement("menupopup");
var mainPopupSet = document.getElementById("mainPopupSet");
mainPopupSet.appendChild(undoPopup);
}
while (undoPopup.hasChildNodes())
undoPopup.removeChild(undoPopup.firstChild);
let tabsFragment = RecentlyClosedTabsAndWindowsMenuUtils.getTabsFragment(window, "menuitem");
undoPopup.appendChild(tabsFragment);
undoPopup.openPopupAtScreen(0, 0, true);