Oh, duh, I know why.

That’s a file that seems to he hardcoded in the plugin to be delivered using http. That causes the Dreaded Mixed Content warning in IE, so I added it to the list of files that the Mavis HTTPS redirector always sends down as https (along with wpsc_user_dynamic_js. however, that file doesn’t seem to impact the overall speed of page delivery).

Not an ideal solution, but it worked.

I guess the proper solution would be to make those two files come down using the correct delivery protocol (https when on a secure page, http otherwise). I was never able to find a working solution to this in the forums, which is why I tried the redirector solution.

I’ve done a smidge more investigation.

What’s going on is that with each request, index.php is getting run with parameters to generate a custom css for that category, which is then used to render the category. It’s kind of a clever way of doing it, but something of a performance killer.

Since I’m not using custom stylesheets per category, I decided to save a static one rather than render a new one with each access.

using wget, I connected to http://www.seattlelumin.com/index.php?wpsc_user_dynamic_css=true&category=1 and saved the response into css/category.css. I then edited theme.functions.php to replace this line:

wp_enqueue_style( ‘wp-e-commerce-dynamic’,$siteurl.”/index.php?wpsc_user_dynamic_css=true&category=$category_id” , false, $version_identifier, ‘all’ );

with this line:

wp_enqueue_style( ‘wp-e-commerce-dynamic’,WPSC_URL.’/css/category.css’ , false, $version_identifier, ‘all’ );

Now I know I’m getting all the stylesheets that I need, and much higher performance.

I suggest that the devs consider a better performing method of sending down custom stylesheets for each category.

well, what do ya know…I’m not the first one to run into this problem; someone already even made a plugin to solve it:

http://wordpress.org/extend/plugins/disable-wp-e-commerce-dynamic-style-sheet/installation/

Essentially, it deregisters the dynamic stylesheet. It’s kind of a bandaid solution, but it seems to work.

My code-editing solution, by the way, was this:

1) create the static css:
cd <PLUGIN ROOT>
mkdir css
wget “http://<DOMAIN NAME>/index.php?wpsc_user_dynamic_css=true&category=1″ -O css/category.css

2) change line 185 in version 3.7.8 wpsc_includes/theme.functions.php from this:

wp_enqueue_style( ‘wp-e-commerce-dynamic’,$siteurl.”/index.php?wpsc_user_dynamic_css=true&category=$category_id” , false, $version_identifier, ‘all’ );

to this:

wp_enqueue_style( ‘wp-e-commerce-dynamic’,WPSC_URL.”/css/category.css” , false, $version_identifier, ‘all’ );

And save.