I upgraded moodle from 2.0 version to 2.2.1. After upgrade, when I switch to different theme, it always showed the stardard theme. I thought it maybe some problem happening during upgrade. So I installed a fresh new copy of moodle 2.2.1, It still the same. The theme always standard, the default one.
I had back up 2.05, so I switched back. It was okay. see the screenshot the top part is the theme selector for moodle 2.05, the bottom part is theme selector interface for moodle2.2.1.
I am not sure whether this is bug for moodle2.2.1. If anyone knows why it happens, how to fix it, please let me know