My double pane Herr windows have a plastic strip in the bottom of the track. It has has holes every 2 inches in it to let the water exit under the strip and out the slits on the outer frame. Over time dirt fills the holes and restricts the water from exiting. Water will fill the track and leak near the corners if they plug the drain slits. Once the track is dry, use a curved pick and lift the strip and vacuum the bottom of the track. I do this a couple of times a year. I have even used compressed air to clean the slits from the outside.
Also, on mine there is a rubber track plug strip to help to keep water from getting into the track on the outside. It is wedged in and pulls out for cleaning. When you reinsert it, start at the bottom and butt it up to the window and work it around the slot and if it is too short, the gap is at the top.
06 Hurricane 34FT WH W20 Chassis 8.1L 120K, Steersafe, Koni Shocks, DIY Trac Bar, Tri-Metric 2025RV Battery Monitor, 4-6V Batteries, Scan Gauge 2, Crossfires, 735W Solar Morningstar MPPT-60, KVH R5 In-Motion Sat, XM Radio, 07 Chevy Malibu Maxx Toad, Falcon 2, Brake Buddy, Escapee