Only disable wpautop on the main TinyMCE instance for the page (#8229)

lib/compat.php

@@ -73,18 +73,19 @@ function _gutenberg_utf8_split( $str ) {
  * Disables wpautop behavior in classic editor when post contains blocks, to
  * prevent removep from invalidating paragraph blocks.
  *
- * @param array $settings Original editor settings.
- * @return array Filtered settings.
+ * @param array $settings Original editor settings.
+ * @param string $editor_id ID for the editor instance.
+ * @return array Filtered settings.
  */
-function gutenberg_disable_editor_settings_wpautop( $settings ) {
+function gutenberg_disable_editor_settings_wpautop( $settings, $editor_id ) {
  $post = get_post();
- if ( is_object( $post ) && gutenberg_post_has_blocks( $post ) ) {
+ if ( 'content' === $editor_id && is_object( $post ) && gutenberg_post_has_blocks( $post ) ) {
  $settings['wpautop'] = false;
  }
 
  return $settings;
 }
-add_filter( 'wp_editor_settings', 'gutenberg_disable_editor_settings_wpautop' );
+add_filter( 'wp_editor_settings', 'gutenberg_disable_editor_settings_wpautop', 10, 2 );
 
 /**
  * Add TinyMCE fixes for the Classic Editor.