General Styling / Fonts

Hi,
In Enfold Child functions.php I added the following code to import the Montserrat Google Font

add_filter( ‘avf_google_heading_font’, ‘avia_add_heading_font’);
function avia_add_heading_font($fonts){
$fonts[‘Montserrat’] = ‘Montserrat:100,100italic,300,300italic,400,400italic,700,700italic&subset=latin,cyrillic-ext,latin-ext,cyrillic’;
return $fonts;
}

add_filter( ‘avf_google_content_font’, ‘avia_add_content_font’);
function avia_add_content_font($fonts){
$fonts[‘Montserrat’] = ‘Montserrat:100,100italic,300,300italic,400,400italic,700,700italic&subset=latin,cyrillic-ext,latin-ext,cyrillic’;
return $fonts;
}

My problem is that when I try to change something in General Styling , for example custom CSS, the selected font in the FONT tab is always selected Arial by default.
So. all the time I have to choose Montserrat to bring the font alive again.
Is there any permanent solution to have Montserrat selected by default?

Thank you in advance