Side window leak

photon

I'm not sure how to post to an appropriate area so I hope you'll forgive me if this is wrong. I chose this category as it might be a maintenance/repair issue. This relates to a 2014 T@B L. In a heavy rain, when stopped camping, we noticed drips running down the inside of the door side window which then ran inside onto our seat cushions. I'd like advice on how to seal the window and have a few questions. 1. Can it be easily removed so as to add caulking at the top? I'm not familiar with how the window is mounted and sealed at the factory so any information and pictures would be welcome. 2. Is it better to add caulk along the top of the window where it meets the trailer? 3. What kind of caulking should I use? Is any caulking rated for exterior use ok? Thanks in advance to any and all for their help. George