Only display notification on single post

I think the solution is to check if it’s the main query. WordPress has a function for that, is_main_query()

The query that you’re running in your related posts widget is a secondary query, so is_main_query() will return false.

You can take advantage of that, by changing your code like this:

if ( ! is_main_query() || ! is_singular() )
return $content;

Related Posts:

  1. Remove option to allow trackbacks/pingbacks from post page options
  2. Display posts by month
  3. How to get 2 or multiple custom post types in wordpress functions.php
  4. Creating bulk posts with Youtube videos
  5. Hide wordpress field if data is empty in post!
  6. Custom posts in different columns style
  7. What file have I to create in my custom WordPress theme to show all the post belonging to a specific category?
  8. Update if post with specific title exists
  9. Auto create description in post
  10. Add multiple HTML attributes to an Elementor button
  11. How to update custom fields using the wp_insert_post() function?
  12. Why have on every line
  13. WordPress and event-driven programming – what is it about?
  14. Admin Bar (Toolbar) not showing on custom PHP file that loads WordPress
  15. Set the transport of the Customizer ‘header_image’ core setting to ‘postMessage’
  16. Limit the Excerpt field in WP-Admin in words
  17. delete an array element when its date expires
  18. New Plugin Review
  19. Use template for posts with a particular category grandparent
  20. “before delete post” action fire when the post is updated?
  21. Random Default Avatar Function
  22. Automatically add custom CSS to new posts using a category template
  23. Query all posts of a custom taxonomy term
  24. Customizer: Output default value in Customizer CSS
  25. Taxonomy linked to pages
  26. Displaying the last post on static homepage
  27. Create another “Display Site Title and Tagline” checkbox, “Header Text Color” setting and control
  28. Can’t get wp_insert_post to work
  29. Why not yield/iterable in posts interface?
  30. Converting HTML Template to WordPress Theme
  31. WordPress Custom Fields (Checkboxes with multiple values)
  32. Can I install/embed WordPress on a ‘single page’?
  33. 200 Rewrite blog post links
  34. Automatically create child pages and grandchild pages when saving a (parent) page
  35. How can I add extra word in permalink when someone click download button?
  36. Using $wpdb (WPDB class) ‘replace’ with multiple WHERE criteria problem
  37. 404 error when I acess the second page of post-type
  38. How do I add a custom css to all posts without affecting homepage css? [closed]
  39. Which PHP page is the Default Posts Page
  40. Advanced Custom Fields not displaying
  41. retrieve post data and insert it in seperate static html page without WordPress
  42. Exclude posts with specific metadata from search?
  43. Copy taxonomy terms from one post to another programmatically
  44. Add data-id attribute to child page links
  45. Display Youtube Time Automate from Key
  46. How to fix this PHP warning in WP-Admin after upgrading to 3.1.2?
  47. How to catch wordpress post ID when it’s published
  48. Find Site ID From WP_Post
  49. Where is the PHP code generating an element?
  50. Basic wpdb update question
  51. Check class_exists before class definition / Doxygen problem
  52. WordPress upload file size error even after raising php limits
  53. WordPress widget and customize.php not working in Ubuntu16.04 VPS
  54. How can I get “Previous” and “Next” to show in the navigation besides the links?
  55. How do i wrap woocomerce attribute in list?
  56. Is it possible to add a custom page to a free WordPress site? [closed]
  57. save metabox with new values _wp_page_template
  58. Saving a post ID to use in a form elsewhere on website
  59. How to Fix an Archive.php That Displays All Posts?
  60. pagination broken – clicking next displays “page not found”
  61. Create condition for Author bio Social Links
  62. remove specificly the last tag in all posts
  63. Add posts to custom table in database instead of wp_posts
  64. How to show categories and date on posts
  65. Woocommerce template file outputting tags
  66. Trying to update Woocommerce meta values
  67. If Statement is Ignored?
  68. Query on a repeater date (acf)
  69. Trying to show the category of a post in the post display
  70. Split post or page content in two or more columns
  71. Check the database for a postmeta field
  72. Create “blank” admin page without having admin-bar/admin-menu for faster load
  73. Send POST request to Flask app from functions.php file
  74. Create Schema in WordPress with PHP
  75. Send Notification after post published was working but stopped after the last WP update
  76. How to insert text into post based on category – via single.php file
  77. Add wp posts to cutom masonry grid
  78. Generate random access token to a post page
  79. How to associate dynamic PHP page for chosen WordPress tag?
  80. Is there a way to have chunks of a page’s content expire?
  81. Where can I find the declaration of `$_wp_theme_features`?
  82. Static home page ignored
  83. How do I routinely extract the thumbnail of the most recent post?
  84. Showing the project type in HREF
  85. ‘posts_per_page’ in costum page type
  86. Display tab title as ‘blog tagline | blog title’
  87. My customizer’s setting doesn’t set to the default and needed to click the control’s “Default” button before it’ll be set
  88. List of child pages fetch next results at link click
  89. Showing custom field contents without listing description
  90. Check if values exists DB
  91. Pagination on Custom Loop
  92. Show a Category Specific Info Box
  93. error with WP custom form
  94. MySQL Engine vs. Charset
  95. Select area and checkbox data is not saving?
  96. How to modify this function to exclude also the post belonging to a specific category?
  97. In reading settings posts are set to “blog” and I have page-blog.php but no posts
  98. Set post to draft if matching word is found in the post
  99. WP Custom tables query
  100. Disable single posts, but keep archive