HTML 4.0 Transitional and Quirks Mode

[Ari Feldman]

I noticed that when the DOCTYPE of a page is set to HTML 4.0 
Transitional, Mozilla enters quirks mode and, among other things, 
ignores certain CSS attributes. However, if the DOCTYPE is 4.0 Strict or 
4.01 Transitional or Strict, Mozilla does not enter quirks mode. Is this 
a bug, or is there some reason why HTML 4.0 transitional should be 
handled in quirks mode?