Here's a basic class tree for some of the classes ...

Pageent (base class for any object on a page).
|
+--Basic_Frame
|  |
|  +--Cached_Frame
|  |  |
|  |  +--Image_Frame
|  |  |
|  |  +--Text_Frame
|  | 
|  +--Raster_Frame
| 
+--Group (has list of pagents)
   |
   +--Page

Document (has list of Pagents and list of Text_Streams)

Text_Frame <- two-way knowledge -> Text_Stream


Todo: Fix filewatcher so it doesn't stat() all the time ...