I have the same problem with a greyed out screen.
The hack of smccombs works well but my next problem is that I need that color picker so I have to figure out for a other solution.
If you do not use a Child theme then you can still apply the hack, just make sure that the hack is made unkept with a theme up.
I use Avada 4.0.3 because of reasons.
I do not know yet whether the existing function is the same in the newer versions as well.
Add the thick printed line of code to the already existing function in functions.php
$ vim wp-content/themes/Avada/functions.php
/**
* Modify admin CSS
*/
function avada_custom_admin_styles() {
echo ‘<style type=”text/css”>.widget input { border-color: #DFDFDF !important; }</style>’;
echo ‘<style type=”text/css”>.wp-color-result { display: none !important; }</style>’;
}
add_action( ‘admin_head’, ‘avada_custom_admin_styles’ );