Getting the front "wing/vent" windows to seal agains the door?

Not long after I bought my '72 four-door, I noticed water in the front doors are washing it. I figured it was just the lower window seals and didn't think much of it since I've got some time before the rainy season.

Turns out, the leak is actually a sizable gap between the bottom rubber frame thingie of the vent window and the exterior door skin.

I can push the window outward to get rid of the gap.

Is there some way to keep it pushed out, or do I need to replace the vent window frame/seal?