testBug1607766() {
    setUpAnchor('abc', 'def');
    setUpRealEditableField();

    const elem = fieldObj.getElement();
    const helper = new TestHelper(elem);
    helper.select('abc', 1, 'abc', 2);  // Selects 'b'.
    // Dispatching a selection event causes the field to cache a selection
    // util, which is the root of the bug.
    plugin.fieldObject.dispatchSelectionChangeEvent();

    plugin.execCommand(Command.MODAL_LINK_EDITOR, linkObj);
    /**
     * @suppress {visibility,strictMissingProperties} suppression added to
     * enable type checking
     */
    dom.getElement(LinkDialog.Id_.TEXT_TO_DISPLAY).value = 'Abc';
    events.fireClickSequence(plugin.dialog_.getOkButtonElement());

    // In IE the unit test somehow doesn't cause a browser focus event, so
    // we need to manually invoke this, which is where the bug happens.
    plugin.fieldObject.dispatchFocus_();
  }
Regression test for http://b/issue?id=1607766 . Without the fix, this
should give an Invalid Argument error in IE, because the editable field
caches a selection util that has a reference to the node of the link
text before it is edited (which gets replaced by a new node for the new
text after editing).
@suppress {visibility} suppression added to enable type checking