Interior leak - Need help!

I need some help with this one. It seems that my 01 model 2619 has developed a leak at the window closest to the front bed, off the dinette.

Now for the really odd part. the leak only happens when the unit is CLOSED, so that to date, only the valance and one half of the curtain get wet. This affects only the front half (upper) of the trailer.

The trailer has been parked in the street in front of my house all winter. I had the unit open about a month ago to show to someone looking at TM's.

The unit IS NOT level, and the street slopes slightly toward the house.

The question I have is this. Is it POSSIBLE that because the unit is not level, water could be somehow bypassing the inner roof seal and then draining down the inside of the unit - thus soaking the curtain and valance?

Or, do I have a dreaded roof leak??

And, why is the leak apparant only when the unit is closed? This is wierd.

Anyone else have this problem or similar ones? If so, how did you handle?

Thanks for your help guys!

Gregg in Portland!