Can't figure out how to stop the navigation from showing through BP Sliding Login

I have successfully installed the BP Sliding Login Plugin. I was able to hide the admin menus using the css #wp-admin-bar {display:none}

The reason I used this method, was adding the line define( ‘BP_DISABLE_ADMIN_BAR’, true );

to the wp-config.php file activated the default WP admin bar. When I added the hide admin bar filter

add_filter( ‘show_admin_bar’,’__return_false’ ); to the same, it broke the site.

Now, the problem I’m experiencing is the Navigation section is showing through the expanded slider.

I thought it might have something to do with the plugins z-index:3 css … that didn’t work!

Now I’m stuck… How do I keep the navigation from showing through the expanded slider???

Demo site:

Thanks for the help,