I'm not sure about the leak when your slide is out, unless it is water left when your slide is in and not seen until putting the slide out. I believe the most common problem with leaks while the slide is in comes from the lack of caulking on the lower facia trim on the slide. Water can leak in and get under the slide between the wood floor of the slide and the membrane covering the underneath of the slide. The water will drip through screws or any other way it can find onto the floor of your coach. Easily fixed by running a bead of caulk along that lower trim.
You can see if this is your issue buy extending your slide, then run the hose on your slide above this trim. Look underneath and see if you find water dripping around any screws or perforations in the membrane.
Hopefully this solves your problem...it did on my Miramar.