Since Plex transcodes to Chromecast friendly format, this bookmarklet will only cast if your original files are already in MP4, OGG, or WEBM format. So, don't expect your AVI files to cast with the bookmarklet.
Plex is awesome, though, and they deserve that $5/mo for making the Chromecast actually useable.
Plex is awesome, though, and they deserve that $5/mo for making the Chromecast actually useable.