Detail:
  RISC OS 4 changes:
  * Font blending for desktop font (based on NC code, but now configurable)
  * 3-D window/menu/iconbar borders
  * Textured menu backgrounds
  * Loss of rubout box in unfilled text+sprite icons
  * *WimpVisualFlags controls various aspects of cosmetic changes above
  * Iconise button "slot" glyph slightly shorter (but only adopted in the RO400
    Resource directory)
  * Command window has front-window flag set
  * Byte at +39 of the window block has gained two new flag bits:
      bit 2 set => this window must never be given a 3D border
      bit 3 set => this window must always be given a 3D border
      (note that ResEd erroneously created windows with both bits set,
      this case is treated as though both bits were clear)
  * Another two colour specifiers on the end of C validation string command
    for icons controls the foreground and background colours to be used when
    the icon is selected...