Freeze First Column in Site View

Agreed. This would be a huge UX improvement. It is otherwise almost impossible to efficiently manage sites without filtering once you have a few extensions set up.

In Dashboard version 4.4.3.2, we added additional table feature that allows you to use this filter:
add_filter( 'mainwp_sites_table_features', 'mycustom_fixed_columns', 10, 1 );

function mycustom_fixed_columns( $table_features ) {

$table_features['fixedColumns'] = "{left:3}";

return $table_features;

}
to freeze first 3 columns.

You can tweak this part: {left:3} to some other value to freeze more or less.

For example you can freeze just first column with {left:1} or first 4 with {left:4}

Thanks, it works, but when using the dark theme the fixed columns get a white background and that looks awful. I would rather suggest a subtle border to the right of these column group or a slightly different dark color as background.