Nickandia

Now I know what it was!

If you have more than two posts, this function is triggered:

<?php twentythirteen_post_nav(); ?>

You can find it in the single.php file.

I simply removed the line of code (didn’t need that function anyway) – and now the single post pages are filling the screen on the Iphone.

Wooho!

Thank you Mark, for helping me!

So, for you others that will find this thread, what I did was:

I found <?php comment_form(); ?> and replaced it with <?php comment_form( array( 'title_reply' => 'Comment here please', 'label_submit' => 'Go go go!' ) ); ?>

Look for more possibilities in the list of arrays that can be found in the link Mark posted.