async applyFocus() {
      await this._waitForDomRef();
      if (this.getRootNode() === this) {
        return;
      }
      const element = this.getRootNode().getElementById(this.initialFocus) || document.getElementById(this.initialFocus) || (await (0, _FocusableElements.getFirstFocusableElement)(this)) || this._root; // in case of no focusable content focus the root
      if (element) {
        if (element === this._root) {
          element.tabIndex = -1;
        }
        element.focus();
      }
    }
Focuses the element denoted by <code>initialFocus</code>, if provided,
or the first focusable element otherwise.
@public
@method
@name sap.ui.webc.main.Popup#applyFocus
@async
@returns {Promise} Promise that resolves when the focus is applied