[Texmacs-dev] Top level menus

[Joris van der Hoeven]

I continued thinking about how the reduce the number
of top level menus. Here are some thoughts.

1. Top level menus should not be dimmed but disappear
   when they are non relevant. This exception seems
   quite essential because of the wide variety of things
   which are potentially possible with TeXmacs.

2. We might regroup the actual Text and Paragraph menus
   in one Format menu with entries Font, Color, Language and Paragraph.
   Changes of format are *always* local changes in environment variables.
   Consequently, the Document menu continues to exist,
   because it deals with global settings for the document.

3. We may rename Structure simply as Text,
   because it concerns markup for text mode.
   When switching to math mode, it naturally becomes Mathematics.
   (I finally like the idea of a Mathematics menu;
   each specific class of markup, like Mathematics, Physics,
   Table, Tree, Graphics, etc. should have its own top level menu.)

4. "View Go Tools Settings" is too much.
   At least one of this menus should be incorporated elsewhere.
   * Maybe Settings in Tools or Edit; we will have a special widget
     later for settings or dedicated browsable pages.
   * Maybe embed Go into the File menu.
   Nevertheless, two of the menus (at least) should stay.