1. Structure and function of menu blocks

1.1. What is a menu block and what an item
Keyword: menu block, menu item, block, item

A MENU BLOCK is a list of ITEMS separated by an empty space. Items
within each block are displayed with the same color. Each ITEM is the
visible string you actually see and can click.  When clicked, a
command line is submitted to the command sentence interpreter.
Complex commands are written as macros.

Some items have filled or empty squares in front of them.  This
squares mark their status.  Clicking on one of them usually does not
result in anything, except the change of the mode reflected by the
change of the box.  Actions happen by clicking other
(not-square-headed) related items within the same menu block, which
use these modes as parameters.

1.3. Loading menu blocks
Keyword: load menu, load_depp_page.com

The file "MAIN_CMDS_NEW:load_depp_page.com" and
"MAIN_CMDS:load_depp_page.com" (for the older releases) load the
initial menu setup.  "MAIN_CMDS:" and "MAIN_CMDS_NEW:"directories
include macros of menu items (".cmds" files) and the "load_...com"
files, which load the additional menu blocks.  Each menu item command
that starts with a "?"  checks weather the file with that name is
present in your working directory, and when found it is processed,
otherwise the default MAIN installation file is taken.

If you want to create your menus, look at the "load" files as examples
and see "MAIN_COM:menu.txt" for further instructions.

1.4. Menu blocks documentation and documentation mode

Documentation files of menu blocks are stored in "MAIN_MENU:"
directory and are accessible also via "MAIN_DOC:dialog_manual.HTML".

When the "Depp pages" window is in the DOCUMENTATION mode, short
description of the pressed BLOCK and ITEM is written to the
standard output window.  The DOCUMENT mode can be turned on or
off either by pressing 'h' on the keyboard or by typing the
command 

> MENU DOCUMENT ON/OFF.