Last Saturday, a faithful support forum participant reported a bizarre bug involving Category checkboxes on the WordPress Post Edit form.  Role Scoper adds “Readers”, “Contributors” and “Editors” boxes – each containing checkboxes to grant access to a specific User or Group.  It seems that some of these checkboxes, when clicked, caused one of the Category checkboxes to be (un)checked accordingly.  Obviously, this is a major bug for sites using Category Roles.

I tracked this error to the WordPress javascript!  WP 2.9 includes a change in wp-admin/js/post.js which makes any plugin-inserted checkbox array an involuntary vehicle of this error.  I have submitted a ticket in the WordPress bug tracking database, but don’t know whether it will be corrected in the WP 2.9 branch.  To manually patch your installation, edit wp-admin/js/post.dev.js as follows:

change:

$('#in-category-' + id + ', #in-popular-category-' + id).attr( 'checked', c );

to:

if ( id && t.parents('#categorydiv').length )
  $('#in-category-' + id + ', #in-popular-category-' + id).attr( 'checked', c );

Then rename post.dev.js to post.js