I have the window like Radar1 has.
The gasket is a fragile design as is the mechanism.
I kept in good working order for 14 years,but I don't think it can be prevented from leaking when placed on the front of the trailer and towed at highway speeds in a heavy rain.
If you must reglue the gasket, keep it lubricated as the window frame put a lot of stress on the gasket when closing.
The mechanism recently broke again so I sealed it shut and installed the power vent that Scamp
is now using. The window now makes a nice natural light
and it no longer leaks
They do make a rockguard kit for it which might help...
I've got one in the hoardware store somewhere. Are you going to Sebring?