You can have the rig pressure tested to find any leaks. THE ONLY SURE WAY to fix a leak is to remove the window and frame and apply new caulk or whatever sealant THE MANUFACTURER recommends then replace the frame onto the rig. My rig uses a butyl caulk tape.
If you take it into a place under warranty you may get the minimum necessary to get you out the door. This may lead to a leak in the wall which will in time rot out the area.
I agree the correct repair is do it yourself if you can. If not do not have the capability then negotiate HOW the repair will be made and inspect closely afterward.
Better yet do the pressure test both before and after the repair at a different shop if possible. It will cost you $200-$300 but the piece of mind will be great.
Also call Forest River and find out who handles warranty repairs in your area. Camping Worlds attitude leaves much to be desired so I would not let it get anywhere near a Camping World. But no repair shop is required to do warranty repairs on your rig. This is not like an automobile there are no federal laws to protect you and force a dealership to repair the rig.
Truth in advertising forces me to say that I feel I was screwed over by Camping World once so I am very leery of them and of the quality of their work. YMMV
Traveling with my best friend, my wife in a 1990 Southwind