WordPress 2.5 Fatal Error wp_register_sidebar_widget

This might be a bug for the new WordPress 2.5 or a bug in the themes of WordPress 2.5. So if you’re a Malaysia WordPress theme designer, take special note of this WordPress fatal error. I experienced this error only after activating a new WordPress theme. And it wasn’t right after activation. It was when I wanted to access the Dashboard from the blog.

When I clicked back to the Dashboard, I was greeted by this scary fatal error:

Fatal error: Call to undefined function wp_register_sidebar_widget() in /path-to-blog/wp-admin/includes/dashboard.php on line 31

Thankfully, there was already a solution online at the WordPress support. But the solution posted there came from another person; Tom Raftery. His research pointed him to another article relating to how the new K2 theme breaks WordPress 2.5.

And, apparently the cause of this WordPress fatal error:

…is because K2 turns off WordPress widgets in favour of its own widget manager and as 2.5 has started to widgetize the Dashboard, you get this error.

Which is why I would advise all Malaysia WordPress theme designers to take this down. Just in case you’re designing based on K2, or having face this WordPress 2.5 fatal error; call to undefined function wp_register_sidebar_widget().

5 thoughts on “WordPress 2.5 Fatal Error wp_register_sidebar_widget”

  1. yeah i realized that yesterday when i was checking my plugins. wonder if 2.5.1 will do any difference cause it’s kinda annoying having the error. i would have to disable and enable the plugin so i can move it to where i want before saving it. and once i have done that the errors appears again, lol :P

  2. Thanks for the tip! Although I don’t use K2 theme, there are many people out there who use it or have themes are that designed based on K2’s code. This is definitely going to be very useful, especially when people started to install WP2.5 (Technorati confirmed that it’s dropping all blogs under Wp2.5, so everyone is kind of forced to upgrade now).

    I love WP2.5, but it’s a shame that they still have not ironed out a couple of bugs, and dumped some of the useful features in WP2.3. For example, they’ve disabled the drag and drop effect for widgets. Gee.

  3. satkuru:
    I’m running 2.5.1 when I had the problem. So I think it’s a WordPress 2.5 issue with the themes.

    teddy:
    Woh, didn’t know about the Technorati part there. As for Wp 2.5, I don’t like the new image positioning bit. I’m so used to having my own styles now they have their own setting included by default.

    Worst part of all, there isn’t a documentation on how I can control the class settings implemented onto the images. -___-“

  4. I also got to know about it recently (last week, to be exact). The news was around for months, but nobody took it seriously until they found that their blogs are listed as spam blogs (due to a WP vulnerability). Anyway in the past, most wordpress themes comes along with three CSS classes for image positioning: .alignleft, .centered and .alignright. WP2.5 leverages on this pre-coded CSS advantage in it’s Tinymce editor, although I’ll now have to add another class for .aligncenter for my CSS since the class .centered is deprecated.

    You do not actually need to edit all the HTML codes and CSS classes for your other images. Simply add the three more new classes into your CSS stylesheet, and copy the attributes from your own pre-defined classes will do.

    The classes that WP2.5 adds into your images are part of their dynamic class feature. For example, if you would want to specifically style an image with an id of 1946, just code for the CSS in the post itself with a class name of .wp-image-1946 will do.

  5. Thanks for clarifying that up for me, Teddy. Due to the number of properties they’re able to add into a single class, it kinda got confusing in there at that point. Anyway, I’ve added the missing stuff into my stylesheet and can now use their default positioning options. :)

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