Directive Hide Fab not working with Lazy loading

My problem is that I followed a tutorial to hide a floating button and it does not work because of the lazy loading. Here is the link of the tutorial:
how can i adjust this please?

I would contact the tutorial author for assistance. It looks like there might be something that needs to changed in the custom directive.

thanks for your comment.
I sent a message to the author for an update of his tutorial.