Other mistake: When the old well needs filling in, for safety reasons, Ryan is breaking up bricks. If you are filling up a well, first, you'd need lots of bricks and stones, heaps more than Ryan's small pile, and, two, why does Ryan have to break up the bricks? They're going into the well - it doesn't matter if they are big or small.
Other mistake: When Laura is directing the planting of a very large palm tree, she says something in Spanish and points to her left; but the man installing the palm moves it to the right - the exact opposite - but suddenly it's perfect.
Other mistake: At the very end, Sherry's wrist is not red, as it should be, after being rammed in the desk drawer by Laura, when she went to get her gun.
Other mistake: When Rosemary is bitten by a spider, Laura says how pretty it was, with red and black stripes on its abdomen. Problem is: we don't get to see its abdomen - Rosemary wipes it away with her hand - and all we saw was black, no red in sight.
Chosen answer: As far as hanging new wallpaper, there is no need to brush on any additional product once it has been pasted to the wall. It appears Helena may be doing an extra decorative step by applying a liquid glaze over the wallpaper to give it a more distinctive look, perhaps creating a sheen effect on the surface. Glaze can also be tinted to give a muted colored tone. It could also be a protective sealant. However, to remove old wallpaper, a product is brushed on that dissolves the old paste so the paper can be easily scraped off.
raywest ★