After adding 10 different Custom Fields, which all have labels, the main WordPress textarea gets overshadowed, and is unlabeled. This makes it unclear to the user what they are supposed to enter there.
Adding an option to label your main textarea would be neat. Maybe wrap it in the metabox to look like the rest of the Custom Fields.
Found a temporary solution, not sure if the postdivrich is the best choice but it works.
add_action('admin_head', 'my_custom_css');
function my_custom_css() {
echo '<style>
#postdivrich {
background-color:white; padding:10px 10px 10px 10px;
font-size: 16px; line-height: 1.5em; font-weight: bold;
}
#postdivrich::before {
content: "Post Main Body";
}
</style>';
}