ARM: uVision 4 IDE - Meaning of symbols in Project Window

To the left of each file named in the Project Window is a rectangular icon which looks like a sheet of paper. Apparently when the icon is blank (white), the IDE cannot find said file. What do the other symbols inside the sheet mean:

* Two rows of dots .... * An arrow pointing down * A small circle coloured YELLOW (apparently the file is write-protected?) * Any others I haven't yet seen ??

Where (if anywhere) in the Keil documentation are these symbols listed and explained? (please post a link if possible). If undocumented, can someone please tell me what they mean.

 RE: ARM: uVision 4 IDE - Meaning of symbols in Project Window

http://www.keil.com/support/man/docs/uv4/uv4_ca_filegrp_att.htm