I'm assuming that you are refering to the scrollbar colors?
The short answer is because your Doctype Declaration (DTD) is correct. Yes, I did say that the way I intended to your DTD is CORRECT.
That's what's causing the colored scrollbars not to work. What you currently have as your DTD is what the W3C recommends:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd" >
If you change it to this:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
your scrollbar colors will show up.
Here's the long version. Every browser already has the DTDs built into them. Netscape Mozilla and others are much closer if not the identical ones the W3C has. IE is different and includes all their cute little proprietary stuff. That's why all their programs like Frontpage, for example, only include the truncated version.
When you include it as you did, the browser looks to the W3C DTD specified in the link -- in your case:
http://www.w3.org/TR/html4/loose.dtd You can actually read the document by clicking that link if you're interested. Anyway, by including that link in the DTD, the browser skips any internal ones and goes to the source -- the actual W3C document. So by including it, it did not contain the information it needs to understand what to do with the scrolling attributes. By excluding it, IE reverts to it's internal DTD and displays it.
Hope that helps.
P.S. I merged your other post with this one because it's related to the same topic.
BTW, I have some elements that are valigned top but when I had the long version of the dtd, it wouldn't work, but now i truncated it, it works as intended. Is this the same reason?