test.js

TXTextControl.addEventListener("ribbonTabLoaded", function(tab) {
    if (tab.tabName == "ribbonTabInsert") {
        // remove tab content from DOM
        tab.elemTab.parentNode.removeChild(tab.elemTab);

        // find associated LI element in the ribbon and remove it
        var elem = document.querySelector("[rel='" + tab.tabName + "']");
        elem.parentNode.parentNode.removeChild(elem.parentNode);
    }
});