I hate when that happens. Chances are, you forgot the white on white bag at home. When I was housesitting for my sister the last time, I looked high and low for a bag of background fabrics. I ended up driving 45 miles to a quilt shop to buy some so I could work on the project. After I got home, I discovered the tote bag with the missing fabric squashed between the seat and the door of the van! It was there all the time and it was the only door I hadn't opened.