In the dashboard area you have the option of 1-4 columns. However when you are adding or editing a new post/page you only have the option of 1-2 columns. I would like to have be able to choose 1-3 or even 1-4 columns. I have lots of custom taxonomy that I would like to arrange more aptly by using more than 2 columns.
It works on a WordPress 3.2 installation I have but not on the current 3.4. It probably only needs a minor tweak but, I can’t seem to figure it out. This is the solution from the link above…
add_action( 'submitpost_box', 'third_column_edit_form' );
add_action( 'submitpage_box', 'third_column_edit_form' );
function third_column_edit_form() {
global $post_type, $post;
//if( 'your-type' != $post_type )
//return;
$side_meta_boxes2 = do_meta_boxes( $post_type, 'column3', $post );
}
add_action( 'admin_print_styles-post.php', 'third_column_css');
add_action( 'admin_print_styles-post-new.php', 'third_column_css');
function third_column_css () {
global $post_type;
//if( 'your-type' != $post_type )
// return;
?>
<style type="text/css">
#side-info-column {
width: 580px;
}
#post-body {
margin-right: -620px !important;
}
#post-body-content {
margin-right: 600px !important;
}
#column3-sortables {
width: 280px;
float: right;
display: block;
min-height: 200px;
}
#side-sortables {
float: left;
display: block;
min-height: 200px;
}
/* Style copied from #side-sortables */
#column3-sortables .category-tabs, #column3-sortables .category-tabs {
margin-bottom: 3px;
}
#column3-sortables .category-tabs li, #column3-sortables .add-menu-item-tabs li {
display: inline;
}
#column3-sortables .category-tabs a, #column3-sortables .add-menu-item-tabs a {
text-decoration: none;
}
#column3-sortables .category-tabs .tabs a, #column3-sortables .add-menu-item-tabs .tabs a {
color: #333;
}
</style>
<?php
}'