I have the same problem, but I use a normal iframe (not iFrame Pro) because iFrame pro doesn’t allow me to set the iframe height to a percentage of the viewport height. Anybody with a solution?
My iFrame code looks like this, but the first name isn’t parsing, it’s just passing on the short code as inserted:
<iframe name="chatpanel" src="https://41.185.31.127:7778/chat27/irc.atrum.org:+6697?nick=[currentuser_firstname]&#Chat27Beta" marginwidth="1" marginheight="1" scrolling="no" border="0" frameborder="0" width="100%" style="min-height: 400px; width:100%; height:80vh;"></iframe>