Update:
For some reason, updating permalinks, deleting .htaccess and refreshing the window where I just updated permalinks seems to fix the issue.
It only works with the Default option, though?
Hey, thanks for replying. That’s good, but isn’t there a way for me to manually edit the plugin? Where is it defined what to paste into TinyMCE? Couldn’t I simply add a few lines of code so that it not only paste in the shortcode, but also <span></span> around it as well?