Ever since I started using the PXS Mail Form plugin in favor of WP-ContactForm for my contact page, I always had problems with it conflicting with the Markdown plugin. Namely, that it disabled the Markdown formatting, and left me with a pile of rubbish.
At the time I decided to keep Markdown and disabled PXS Mail Form, and my contact page took a vacation, but I finally managed to take some time to look a little deeper. Turns out, it’s pretty obvious. Lines 467 through 472:
remove_filter(‘the_content’, ‘Markdown’, 6);
// [… snipped some …]
add_filter(‘the_content’, ‘pxs_callback’, 1);
D'oh. In case that doesn't make sense to you, it's actually taking the `Markdown()` filter *off* and putting its own as priority 1. That's not good. I ended up changing it to:
//remove_filter('the_content', 'Markdown', 6);
// [... snipped some ...]
add_filter('the_content', 'pxs_callback', 14);
So now the line removing
Markdown() is commented out, and I lowered (so to speak) the priority of
pxs_callback() to 14, and it all works great. Just in case someone else runs into this.