[cart] Album theme not appearing when viewing cart

I have an album on my site which uses a custom theme. The theme is a copy of matrix, with a modified header graphic. When I add items to the cart, the theme changes back to the default matrix theme when the cart contents appear. Is this the default behavior, and if so, is there a way to make the cart contents screen show the theme that has been applied to the album, versus the default theme? Here is a link to the gallery so you can see what's happening:

http://www.mapinfoblog.com/gallery/main.php?g2_itemId=20

George

Gallery version = 2.2.1 core 1.2.0.1
PHP version = 4.4.6 cgi-fcgi
Webserver = Apache/1.3.37 (Unix) mod_fastcgi/2.4.2 mod_auth_passthrough/1.8 mod_log_bytes/1.2 mod_bwlimited/1.4 FrontPage/5.0.2.2635.SR1.2 mod_ssl/2.8.28 OpenSSL/0.9.7a PHP-CGI/0.1b
Database = mysqlt 4.1.21-standard-log, lock.system=flock
Toolkits = Exif, Getid3, LinkItemToolkit, NetPBM, Thumbnail, Gd
Acceleration = none, none
Operating system = Linux box62.bluehost.com 2.6.19-1_3.BHsmp #1 SMP Mon Jan 15 07:50:58 MST 2007 x86_64
Default theme = matrix
gettext = enabled
Locale = en_US
Browser = Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.4) Gecko/20070515 Firefox/2.0.0.4
Rows in GalleryAccessMap table = 12
Rows in GalleryAccessSubscriberMap table = 366
Rows in GalleryUser table = 2
Rows in GalleryItem table = 364
Rows in GalleryAlbumItem table = 2
Rows in GalleryCacheMap table = 0