Have any of you guys had experience with the black adhesive on the seal creeping under the Silicon seal, between tray and tile? happened to me 3 times nowIts very common on sites over here, getting more common in domestic applications as well. Its better in my opinion than plumber applied Silicon that wont stick to the dusty wall. However most of them have them too tight around the corners and i have to cut the seal (thus rendering it useless & i fill it with Silicon instead) to get a tile to fit right in. So as Dave says if fitted correctly they seem fine.
Better just tanking the whole thing in my opinion though.