When creating boxes like this, you want to make sure to use a strong adhesive so it doesn't come apart, esp. when filled with candy/goodies.
For the window I used a page protector. The ones I have aren't clear, but have a little bit of texture to them. I still like how it turned out. These came together very quick and easy (the hardest part was deciding on what papers to use) and I plan to make a few more for gifts.