I looked into this a bit more. The reason why you would get an error here is that onDomBind returns the component "{that}". This in turn is used as a focus handler, instead of simply triggering focus. jQuery also has this annoying habit of treating things like func() and fund(undefined) differently, making overriding the default problematic. However, you can use the trigger method instead.

```javascript
                "this": "{that}.dom.magnifierOnOffFocusable",
                "method": "trigger",
                args: ["focus"]
```

However this has an annoying issue of setting focus on page load, which you don't want. Since this is a temporary solution anyways, you might as well just leave what you have.