Comment 1 for bug 798090

I've pretty much nailed down this bug. It happens when a Hotcue is activated (the track was previously paused) and then you hit the play button. Judging from the code this might have been done more as a *feature* than it being an actual bug. For reference, this is the actual offending code, from src/engine/cuecontrol.cpp[649]:

void CueControl::cuePlay(double v) {
    QMutexLocker lock(&m_mutex);

    if (m_bPreviewing && !v) {
    // we're previewing? Then stop previewing and go into normal play mode.
        m_pPlayButton->set(1.0);
        m_bPreviewing = false;
    }

    if (m_bPreviewingHotcue && !v) {
        m_pPlayButton->set(1.0);
        m_bHotcueCancel = true;
    }

    lock.unlock();
}

Where it checks for m_bPreviewingHotcue is where it gets hung up.