Silicone is very waterproof but it doesn't adhere well to surfaces especially if they are porous or not completely clean and free of contaminants. It also should not be in contact with water too long so, water must drain away from the joint. Silicone also does not seal well when applied thin to a surface. The joint should be between 1/8" and 1/4 inch wide and of the same depth with a backer rod or something to form a concave shape to the back side or at least prevent it from filling the joint to deeply. The front side should also be concave. This hour-glass shape ensures that the sealant will stretch before the adhesion to the surfaces fails. But since the sealant failed immediately I would assume the surfaces were not cleaned properly. Old sealant is the worst contaminant and the most difficult to get rid of. Silicone is used for joints with a lot of movement between dissimilar materials like at exterior aluminum windows. If this joint will not move much you might consider a polyurethane sealant which is less flexible but more resistant to water contact and adheres to surfaces far better. It is preferred over silicone in marine applications.

We have been using our Miele for a week. Ive found that my silicone baking pans do not get clean. I scrape off what I can - but its a baking pan - so there is food left behind. Each time - I end up hand washing after it runs in the dw. Am I doing something wrong?

If one heats silicone to destruction, the most likely solid product will be silicon dioxide, or quartz, the primary compound in glass. It can be dissolved in hydrofluoric acid, but don't try this at home, or anywhere else. The metal it has coated may be dissolved faster and the fumes are toxic. The good news, such as it is, is that if the unbonded "glass" dust is vacuumed up or wiped up, the residue is unlikely to get in one's food, and would not be more harmful than eating outdoors in a dust storm, or eating a mud pie if one were young enough. Wiping may be better than vacuuming, depending on how well one's vacuum keeps dust out of its motor. Moving glass dust -- much like regular dust but possibly finer -- is not what you need in the vacuum's motor or in the exiting air. I would be concerned about the dust that makes it into the convection fan passages that are difficult to get to. Some consideration of the cost-effectiveness of oven replacement may be called for. In general, my condolences for the disasters that have befallen you.

I agree with the above.... And I'd add that if anything won't stick, it would be the new stain over old silicone residue. Also, if the interface that you are referring to is the wood sash stile/rail to the glass, that generally does not get a bead of silicone or sealant externally anyway. Someone may have added that after the fact.