Ken--
When Jack originally wrote the GUI documentation (for AUI, XTREE, parts of INFLD) a couple years ago, we put it in its own doc file, but that was mostly so we had something new and interesting to give out at the A-Shell conference (Nov 2004). We talked about having a separate GUI doc, but in the end decided that since all the GUI stuff was done with subroutines, the stuff should be in the XCALL Ref. Also, we were reluctant to create another doc just because it's one more thing to keep track of, etc.
If you or anybody else would like to have the GUI topics isolated in their own doc (which equates to a major section in the consolidated AshRef), I wouldn't mind reorganizing things accordingly. The new doc would probably be called "GUI XCALL Reference" or something like that.
Comments welcome from all.