Question

When I click, or scroll mouse wheel, and it’s pointer is at the right part of the screen, where there no text, emacs shows help-menu like this:

Press PageUp key to reach this buffer from the minibuffer.
Alternatively, you can use Up/Down keys (or your History keys) to change
--/.../--
In this buffer, type RET to select the completion near point.

Possible completions are:
e==>Emacs Tutorial                     E==>Emacs Tutorial (choose language)...
--/.../--
a==>About Emacs                        A==>About GNU
=================================================================================

;; here my work buffer

=================================================================================
Help (up/down to change, PgUp to menu): e==>Emacs Tutorial

It is very disturbing, i have to press C-g to return to edit.
How to disable this feature?

P. S. I tried to press C-h k < LMB at right>, but it doesn’t show the code of the key, it shows that menu again.

edit(in response to Stefan):

after pressing: aaa <LMB at right> C-g C-h l i see the following sequence:

… a a a ESC
[ M SPC \300\256 6 ESC [ M # \300\256 6 C-g C-h l

As I found, those symbols: \300\256 and 6 are dependent on the position of the cursor when i click. \300\256 is a smth like horisontal coordinate, 6 is a vertical coordinate.

I investigated it further: the menu appears when y coordinate from an ordinary symbol like a or } or DEL(actually it is the last ordinary symbol) becomes a code like \300\200( this is the first value, which cause the help-menu). As a unicode symbol table tells, DEL code is U+007F(0b01111111), and the next value will be U+00800(0b10000000) (Padding Character) which is in another table: C1 controls and Latin-1 supplement

I use GNU emacs 23.2.1, over PuTTy ssh client.

Answer 1

This is actually a bug.
Here is a workaround for it:

;; Disable menubar
(menu-bar-mode -1)

;; Workaround for "mouse on menu-bar" bug
(defun transform-to-start-event (event)
  (let ((y0 (second (window-inside-edges (selected-window))))
        (x0 (first (window-inside-edges (selected-window)))))
    (let ((x (- (car (third (second event))) #x3fff00 x0))
          (y (- (cdr (third (second event))) y0))
          (time (fourth (second event))))
      `(down-mouse-1 ,(posn-at-x-y x y (window-at 0 0) t)))))

(defun tmm-menubar-mouse (event)
  (interactive "e")
  (let ((evt (transform-to-start-event event)))
    (push (cons 'up-mouse-1 (cdr evt)) unread-command-events)
    (mouse-drag-track evt t)))

It deactivates the menu bar, but i didn’t need it anyway.
Also it doesn’t handles selection, and scrolling properly, but at least, it positions point correctly.