Dashboard Rattle Problem

[BarryY]

We've been focusing on the area under the cowel but the sound always seems like it comes from the area where the dash meets the windshield. It also seems to be a type of sound of plastic rattling (rather than a metal squeek).
One new observation is that when I removed the hardtop and just have the soft top closed, the rattle has gone away for the time being. However I need to monitor this longer because the first time I heard the rattle was with the top down.
If you have any other observations, please share them...thanks