test.js

// remove the "Insert" menu item
TXTextControl.addEventListener("contextMenuOpening", e => { 
	
	// check if e.items contains an entry where property text == "Insert"
	const index = e.items.findIndex(i => i.text === "Insert");

	// if so, remove it
	if (index > -1) {
		e.items.splice(index, 1);
	}

})