[wp-testers] r7331 Media Library error

[Kirk M]

In the "Manage/MediaLibrary", when selecting a any link in the "Media" 
column brings up the selected image's edit page as usual, "Settings", 
"Plugins" and "Users" disappears from the top right of page and the 
following warning is displayed at the bottom of the page:
*
Warning*: Cannot modify header information - headers already sent by 
(output started at 
/home/longmead/public_html/just-thinkin/wp-admin/admin-header.php:26) in 
*/home/longmead/public_html/just-thinkin/wp-includes/pluggable.php* on 
line *688

*All plugins are deactivated during this test.

On my other test site currently running on r2998 the same thing occurs 
with the exception of slight change in the warning (different line #):

*Warning*: Cannot modify header information - headers already sent by 
(output started at 
/home/longmead/public_html/just-thinkin/wp25-test/wp-admin/admin-header.php:26) 
in 
*/home/longmead/public_html/just-thinkin/wp25-test/wp-includes/pluggable.php* 
on line *687

*Again, no plugins activated.

Has anyone else seen this?