Ok, I wrote up the following to add to my FAQ eventually. It is intended to help walk you through patching your plugin/theme.
Patching Your Plugin/Theme
Should you wish to attempt this patch yourself, you can modify your conflicting plugin/theme’s admin menu Walker class.
1. Find the class that extends the Walker_Nav_Menu. As a hint, it is filtering wp_edit_nav_menu_walker and you might even be getting a warning about it from Nav Menu Roles. Example:
add_filter( 'wp_edit_nav_menu_walker', 'sample_edit_nav_menu_walker');
function sample_edit_nav_menu_walker( $walker ) {
return 'Walker_Nav_Menu_Edit_Roles'; // this is the class name
}
2. Find the file for the extending class. In my plugin this is in a file located at inc/class.Walker_Nav_Menu_Edit_Roles.php. I can’t know *where* this file is in your plugin/theme. Please don’t ask me, but here’s what the beginning of that class will look like:
class Walker_Nav_Menu_Edit_Roles extends Walker_Nav_Menu {}
Note that the class name is the same as the class name you found in step 1.
3. Find the start_el() method
In that file you will eventually see a class method that looks like:
function start_el( &$output, $item, $depth = 0, $args = array(), $id = 0 ) {
4. Paste my action hook somewhere in this method!
In Nav Menu Roles, I have placed the hook directly after the description, ex:
<p class="field-description description description-wide">
<label for="edit-menu-item-description-<?php echo $item_id; ?>">
<?php _e( 'Description' ); ?><br />
<textarea id="edit-menu-item-description-<?php echo $item_id; ?>" class="widefat edit-menu-item-description" rows="3" cols="20" name="menu-item-description[<?php echo $item_id; ?>]"><?php echo esc_html( $item->description ); // textarea_escaped ?></textarea>
<span class="description"><?php _e('The description will be displayed in the menu if the current theme supports it.'); ?></span>
</label>
</p>
<?php
// Add this directly after the description paragraph in the start_el() method
do_action( 'wp_nav_menu_item_custom_fields', $item_id, $item, $depth, $args );
// end added section
?>
