I don't know if this has been spoken of here, but there is a peculiarity with Vegas and displaying your preview and a source display in the trimmer on the same screen. if you have your trimmer window set to show video monitor and it's on the same display as your preview window is, then you will likely have seen a weirdness in the way that the video shows up in your preview window. They appear to have to both be the same size, but if you have dual display with the preview and trimmer windows on separate displays then this isn't an issue for your, or if you just turn off your show video monitor in the trimmer when you're done using it, then it shouldn't be a big deal either, plus - it does have a perhaps inadvertent benefit of making the displays the same as each other for comparison when making a 3 point edit ( or maybe this is why it was done this way in the first place ).

Dave