ob_start on 'admin_head' action broke in 2.5.1

[rainwater]

We currently use a 'admin_head' filter in our theme to hide specific categories on the post-new.php page for specific user roles. However, in 2.5.1, there is some type of change that results in the output dying and not getting past the html head code. Here is an example of the code:

function hide_cats_shell() {

$out = '<div></div>'; real code would output only specific categories
return $out;

}

function hide_cats_start($c) {

return preg_replace('|<div id="categories-all" class="ui-tabs-panel">.*?</div>|sie', hide_cats_shell(), $c);

}

function hide_cats($unused) {

if(preg_match('|/wp-admin/post-new.php|', $_SERVERREQUEST_URI?)) {

ob_start('hide_cats_start');

}

}
add_action('admin_head', 'hide_cats');

The above code now results in the only the head html being output to the browser. Because of this we have had to downgrade our site to 2.5.0 in order to continue using it.

[ryan]

Maybe due to [7805]

[rainwater]

I tried commenting that out, but the issue still occurs. It does appear it could cause problems by dropping the buffer there though. Unfortunately, there must of been another change causing this particular issue.

[ryan]

Milestone 2.5.2 deleted

[DD32]

Given that this has been broken for 2 major releases aparantly, I'm closing as invalid, on the thought that this is most likely invalid under todays trunk, Re-open if necessary