I've just gotten into Mapmaking thanks to Crash's tutorials, and so far, when I'm moving the screen around, the props will turn into a colored box. This is especially frustrating when I'm using Boojum Snark's TF2 Resource Pack, as everything will appear to be a yellow or pink box. I doubt it's a compiling log issue, as it appears as boxes when I'm building the maps. "How do I fix this?" is essentially what I'm asking, as I've just starting this less than a day ago.