Notice: Undefined index: filter in …wp-includes/default-widgets.php on line 382

That a Notice, not an error. Turn off notices in your PHP installation, or turn off the WP_DEBUG mode.

More importantly, turn off display_errors. The display_errors setting should never, ever, be enabled on a production site. That’s for debugging only.

Related Posts:

  1. WP_Widget deprecated error in WordPress V4.3
  2. Why will using __construct instead of widget_class_name when creating widget trigger out of memory error
  3. Extending WP_Widget throws error when Monster Widget used
  4. Debugging / displaying errors in WP_Widget->form()
  5. Can I use wp_widget_rss_output to show my site’s feed in the dashboard?
  6. How can I use the built in WordPress “browse link” functionality?
  7. Code for Recent Posts Widget
  8. Modifying the default search widget
  9. Prevent widgets removal
  10. Is there a way to add more tags to the tag cloud?
  11. How to build widget with arrays inside arrays?
  12. How do I save data from submitted form from widget
  13. Why Can’t wp_editor Be Used in a Custom Widget?
  14. Add div class to only one widget
  15. How to use control_callback when creating a widget via functions.php or plugin?
  16. Disable default WordPress widgets in sidebar
  17. Updating to Version 4.5 bumped my “main sidebar” widget out of place
  18. How can I delete all inactive widgets?
  19. Call sidebar from a template
  20. Adding classes to dynamic sidebar
  21. Widget Area: Modify $param[‘xy’] from widget-$n
  22. Need help adding additional controls to a custom widget
  23. Why do none of my widgets have a title?
  24. Defer Code in Widgets – Page Speed
  25. Where are widget configurations stored?
  26. Adding a widget to a string of HTML
  27. How to add a class to a link in text editor
  28. WordPress widget new instance creates content duplicates
  29. Remove/Add widgets from/to the Available Widgets pool
  30. Remove/Unregister or hide a widget added by a plugin
  31. Check if widget is active
  32. Radio buttons in widget not saving
  33. Pre-install widgets in WP-Admin
  34. Subscribe2 widget with choosing categories?
  35. How to change plugin`s template (view) correctly?
  36. Showing a Thickbox (tb_show) does nothing
  37. How do I add a widget from an Android phone?
  38. Error gets thrown when calling require_once on widget.php
  39. Getting a div wrapped around two widgets
  40. How to create a widget that accepts html input?
  41. Widget changes in customizer ajax error to many options?
  42. How to Add TinyMCE to widget
  43. How can I get the first section of a page 100% width, while the rest will have a sidebar? [closed]
  44. Modify ‘Sizes’ Attribute for Images with Specific Class
  45. Dynamically add content to an existing widget area
  46. Issue understanding and using WordPress filters and actions
  47. How can I inject html after the [x]th widget inside a Sidebar? [duplicate]
  48. How do I create a widget to embed the code for a sign up form, so that the sign up form appears on every page?
  49. Tabs and Category Widget
  50. How to add the same widget twice?
  51. How to hide widget if current category has no posts assigned to it?
  52. ‘is_author()’ logic in widget for author only
  53. Undefined Variable in my widget
  54. Update widget form after drag-and-drop “only specific plugin”
  55. Recent Comments from Specific Category Widget
  56. Different sidebars not changing
  57. How to make widget appear conditionally
  58. How Migrate a Legacy Widget to block?
  59. Ampersand breaking Widget title
  60. How to allow editing of text in sidebar?
  61. Shortcode into widget
  62. How to show avatar of current logged in user in a widget
  63. Got a problem with a widget
  64. Widget control – putting a slideshow in the widget area
  65. Extending the WordPress Recent Posts Widget
  66. How to paste widget to a specific page
  67. How do I find out which
  68. How to update a widget data?
  69. An archive widget, coming from nowhere on my posts and pages
  70. custom widget not saved to sidebar
  71. When editing in block editor, the post/article gets under the floating widgets
  72. Recently changed domain name. Home page widgets are now not in the customize menu yet still being on the page
  73. Make widget with media upload repeatable
  74. Is it possible to dynamically output the name of the widgets?
  75. wp_registered_widgets doesn’t contains my widgets
  76. How can I write this code snippet so that it echo’s the response when submitting empty fields?
  77. What is the difference between widget object and widget instance?
  78. Apply two different styles to Wiget Titles along with a decorative line
  79. Widget text color change
  80. Widget to embed youtube video
  81. How to make featured area?
  82. Checking if widget has title not working
  83. wp_list_categories + widget
  84. How can I add widgets to the category page?
  85. Remove default WordPress widgets
  86. Disable wordpress widget automatically on error
  87. Can I add a widget to the of my site?
  88. Widget dynamically add new input field
  89. How to show widget in frontend?
  90. Widget Development – Displaying dropdown content
  91. How do I stop out of stock items from appearing on my WooCommerce site when using the Layered Nav widget [closed]
  92. Single Widget Multi Sidebar
  93. An issue with register_sidebar and the admin interface
  94. page url in shortcode
  95. iframe/embed vid in text widget loads outside container and moves around when scrolling the page?
  96. Widget on home page displays wrong time compared to same widget on inside pages
  97. Widget logic not working
  98. Widgets in PHP files?
  99. Text Widget Not Working
  100. Sample widget code which get data(1-5 record) from Wp_Admin panel and display to Homepage(WordPress Custom Theme)