Mixing Audio doesn't seem to work

Hey guys,

GREAT Software! Just finished the first episode of my new podcast.

One problem I noticed, I can get two audio tracks to play together at the same time. If I have a video track with audio and an audio track, that works fine, but two audio tracks won't seem to play together, what am I doing wrong?

Maybe the same problem that I encountered, as described in my topic about the timeline giving wrong information?