Ability to add custom column to list pages (plugins,users,links,comments,terms,ms)

[axelseaa]

Currently the ms-themes page has a hook to add in custom column content, however it does not have a hook to add in a custom column heading.

I am requesting that the attached patch (or something similar) be implemented to permit plugins to add columns to the themes table.

After further digging, this also appears to be a problem in:

wp-admin/includes/class-wp-plugins-list-table.php
wp-admin/includes/class-wp-users-list-table.php
wp-admin/includes/class-wp-links-list-table.php
wp-admin/includes/class-wp-comments-list-table.php
wp-admin/includes/class-wp-terms-list-table.php
wp-admin/includes/class-wp-ms-themes-list-table.php

Only have of the necessary hook/filter is there to do the job - because of this I'm changing the filling back to bug.

20913.patch addresses all issues I discovered

There's manage_{$screen->id}_columns filter which should work in all those cases:
http://core.trac.wordpress.org/browser/tags/3.3.2/wp-admin/includes/class-wp-list-table.php#L89

For Network Admin > Themes screen, it would be manage_themes-network_columns.

Ah, yeah - that does work. I missed that last night because the inconsistency of how the other pages are done confused me.