For your CD Burning Gap issue, read this:
http://yabb.jriver.com/interact/index.php?topic=43447.0For the other issues, one problem you're having is that MJ8 is really quite old, and most of us are trying to go on memory for how things worked for us years and years and years ago. With my wine-addled brain that's not the easiest task, and a bunch of the rest of us aren't much better!
I'd probably give it another week or two to "mature" (because it
just came out), but you might want to download and try out MJ12. This is a brand new product from JRiver that is completely free and is designed to get a lot of users like yourself "caught up to the rest of us" who use MC12. The two products (MJ12 and MC12) are very similar, with MJ12 being mostly just everything MC is, but limited to Audio and a bit more simplified all around (but not dumbed down).
As for your specific question on disabling the auto-cut of the tracks... I would strongly guess that such an option would exists, but I have no idea where. Someone younger and with a stronger memory will have to step in.