Insert/edit Link Dialog doesnt show

Update1

Checked the admin editor load and found it was executing the following jquery file

file: wp-includes/js/jquery/jquery.js?
version: 1.7.2

In this file there is the following line which is executed on editor load.

f.curCSS=f.css

In the unminified version of this file this reads as

// DEPRECATED in 1.3, Use jQuery.css() instead
jQuery.curCSS = jQuery.css;

Commenting this out produces the same behaviour as the WP User Frontend exhibits on clicking the link button.

Found WP User Frontend wasn’t using this JQuery file at all. Instead it uses

https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js?ver=3.4.2

which is JQuery version 1.8 which doesnt include “jQuery.curCSS = jQuery.css;” and hence the problem.

So the real problem is why is WP User Frontend using the googleapis version and not the local wp-includes version? Which should it be using?

TheProfessor

Resolution

Upon further investigations I found that https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js?ver=3.4.2 was been loaded but another plugin (showtime) using the following script.

function showtime_jQuery_method() {
    wp_deregister_script( 'jquery' );
    wp_register_script( 'jquery', 'https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js');
    wp_enqueue_script( 'jquery' );
}    

//add_action('wp_enqueue_scripts', 'showtime_jQuery_method');

It seems according to this link https://www.ads-software.com/support/topic/notice-wp_deregister_script-was-called-incorrectly plugins like to fix their JQuery version using such code.

Unfortunately using JQuery 1.8 will break WordPress 3.4.2 as seen here.

Solutions

Presently I have four solutions for this problem.

1. Change the JQuery version to 1.7.2 on the offending plugin (or alternatively comment the offending code out as I did which then causes it to default to the current wordpress JQuery version). In this case the Showtime Plugin seems to be quite happy with JQuery 1.7.2. If the given plugin absolutely requires the specified JQuery version try one of the following.

2. Use my original fix which was to substitute wp-includes\js\jquery\ui\jquery.ui.core.min.js with the newer version v1.8.24 from https://github.com/jquery/jquery-ui/blob/1-8-stable/ui/jquery.ui.core.js

3. Insert the code jQuery.curCSS = jQuery.css; where appropriate

4. Wait for a newer version of WordPress that includes an updated JQuery UI.

Conclusion

My investigtions also hint there maybe maybe other side effects of this bug depending on code.

In conclusion this and maybe other bugs in WP User Frontend may be caused by other plugins that use JQuery version substitution.

So before one reports a WP User Frontend bug one needs to disable other plugins to see if they are the cause.

Hope this helps other people who come across this hard to resolve bug.

Cheers
The Professor

Slight correction and additional info

The original script at the top of the last post should be

Original

function showtime_jQuery_method() {
    wp_deregister_script( 'jquery' );
    wp_register_script( 'jquery', 'https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js');
    wp_enqueue_script( 'jquery' );
}    

add_action('wp_enqueue_scripts', 'showtime_jQuery_method');

To fix the offending plugin if it is compatible with JQuery version 1.7.2 alter the plugin code appropriately using one of the following options as a template

Option 1.

function showtime_jQuery_method() {
//    wp_deregister_script( 'jquery' );
//    wp_register_script( 'jquery', 'https://ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js');
    wp_enqueue_script( 'jquery' );
}    

add_action('wp_enqueue_scripts', 'showtime_jQuery_method');

Option 2

function showtime_jQuery_method() {
    wp_deregister_script( 'jquery' );
    wp_register_script( 'jquery', 'https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js');
    wp_enqueue_script( 'jquery' );
}    

add_action('wp_enqueue_scripts', 'showtime_jQuery_method');

Cheers
The Professor