When I choose a different them and click Save Changes on the Admin Bar settings page, I get:
Warning: Invalid argument supplied for foreach() in /.../html/wp-admin/includes/plugin.php on line 626
Warning: Cannot modify header information - headers already sent by (output started at /.../html/wp-admin/includes/plugin.php:626) in /.../html/wp-includes/pluggable.php on line 856
However, when I go Back from the error page and the Admin Bar settings page reloads, the Admin Bar theme hasn't changed - the colors are the same - but the new theme is now the chosen one in the Theme drop down, as if my new choice was stored in the db but not actually applied.
Thoughts?