7. The modeline

7.1. How can I make the modeline go away?

(set-specifier has-modeline-p nil)

7.2. How do you have XEmacs display the line number in the modeline?

Add the following line to your `.emacs' file:

(setq line-number-mode t)

7.3. How do I get XEmacs to put the time of day on the modeline?

(display-time)

7.4. How can one change the color of the modeline based on the mode used? i.e. red for C mode, green for TeX mode etc.?

You can use something like the following:

(add-hook 'lisp-mode-hook 
        '(lambda () (set-face-background 'modeline "red" (current-buffer))
                    (set-face-foreground 'modeline "yellow" (current-buffer))))

Then, when editing a Lisp file (ie went into Lisp mode), the modeline colors change from the default set in your `.emacs'. The change will only be made in the buffer you just entered (which contains the Lisp file you are editing) and will not affect the modeline colors anywhere else.

Notes:

• The hook is the mode name plus "-hook". Ie c-mode-hook, c++-mode-hook, emacs-lisp-mode-hook (ie your `.emacs' or a xx.el file), lisp-interaction-mode-hook (the *scratch* buffer), text-mode-hook, etc.
• Be sure to use add-hook, not (setq c-mode-hook xxxx), otherwise you will erase anything that anybody has already put on the hook.
• You can also do (set-face-font 'modeline font), eg (set-face-font 'modeline "*bold-r-normal*140-100-100*" (current-buffer)) if you wish the modeline font to vary based on the current mode.

7.5. With AUC-TeX, fast typing is hard because the current chapter/section/... is given in the modeline. How can I turn this off?

it's not auc-tex, it is func-menu. from func-menu.el:

(defvar fume-display-in-modeline-p t