Annoying arrow key scroll behaviour in emacs 27

Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

Platform: debian 11.1 "bullseye", amd64
          Emacs 27.1
          Display on windows 10 using MobaXTerm and SSH tunneling

Arrow up and down scroll the window instead of moving the cursor, when
the buffer has more lines than is visible.

Do anyone know what has caused this and how to make it stop?

I.e. I would like to have arrow up and down move the cursor instead of
scrolling the buffer.

Thanks!

Re: Annoying arrow key scroll behaviour in emacs 27

[xenodasein--- via Users list for the GNU Emacs text editor]

Is 'scroll-lock-mode' activate?

Re: Annoying arrow key scroll behaviour in emacs 27

[Tassilo Horn]

Steinar Bang <sb@dod.no> writes:

Hi Steinar,

> Platform: debian 11.1 "bullseye", amd64
>           Emacs 27.1
>           Display on windows 10 using MobaXTerm and SSH tunneling
>
> Arrow up and down scroll the window instead of moving the cursor, when
> the buffer has more lines than is visible.

Are you saying that the behavior changes depending on if the buffer fits
into one window, i.e., in the case where it does the arrows move point
and otherwise scroll?

> Do anyone know what has caused this and how to make it stop?
>
> I.e. I would like to have arrow up and down move the cursor instead of
> scrolling the buffer.

The first thing I'd check was see what `C-h k' says about pressing the
up/down arrows.  The expected answers would be that <up> is bound to
`previous-line' and <down> is bound to `next-line'.  What does it say
for you?

Bye,
Tassilo

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> xenodasein--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>:

> Is 'scroll-lock-mode' activate?

It looks that way: C-h v scroll-lock-mode RET says:

 scroll-lock-mode is a variable defined in ‘scroll-lock.el’.
 Its value is t
 Local in buffer Home.js<authservice.web.users.frontend>; global value is nil

  Automatically becomes buffer-local when set.

 Documentation:
 Non-nil if Scroll-Lock mode is enabled.
 Use the command ‘scroll-lock-mode’ to change this variable.

Not sure what has switched it on?  Not in my own config and not
activated on purpose by me.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Tassilo Horn <tsdh@gnu.org>:

> Are you saying that the behavior changes depending on if the buffer fits
> into one window, i.e., in the case where it does the arrows move point
> and otherwise scroll?

Yes.

And in the case when it scrolls: when it reaches the bottom or top of
the buffer, the arrow key starts moving the cursor instead of scrolling.

> The first thing I'd check was see what `C-h k' says about pressing the
> up/down arrows.  The expected answers would be that <up> is bound to
> `previous-line' and <down> is bound to `next-line'.  What does it say
> for you?

C-h k <up> says:
It is bound to C-p, <up>.

C-h k <down> says:
It is bound to C-n, <down>.

Thanks!

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Steinar Bang <sb@dod.no>:

>>>>> xenodasein--- via Users list for the GNU Emacs text editor <help-gnu-emacs@gnu.org>:
>> Is 'scroll-lock-mode' activate?

> It looks that way: C-h v scroll-lock-mode RET says:

>  scroll-lock-mode is a variable defined in ‘scroll-lock.el’.
>  Its value is t
[snip!]
> Not sure what has switched it on?  Not in my own config and not
> activated on purpose by me.

It looks like this is the culprit.

When I do M-x scroll-lock-mode RET once it says that it switches on
scroll-lock-mode (even though the value was t)

If I do M-x scroll-lock-mode RET again it says that it switches off
scroll lock mode and then the annoying behavious is gone.

Now I just got to figure out what switches the behaviour on (i.e. it's
".emacs bisect time" again...).

Re: Annoying arrow key scroll behaviour in emacs 27

[Michael Heerdegen]

Steinar Bang <sb@dod.no> writes:

> Now I just got to figure out what switches the behaviour on (i.e. it's
> ".emacs bisect time" again...).

Alternatively add (debug-on-entry 'scroll-lock-mode) near the beginning
of your config and restart.  The backtrace should tell you what invoked
the mode, you see which form in which file is currently processed etc.
c to continue.  Then remove the `debug-on-entry' call.

Michael.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Michael Heerdegen <michael_heerdegen@web.de>:

> Steinar Bang <sb@dod.no> writes:
>> Now I just got to figure out what switches the behaviour on (i.e. it's
>> ".emacs bisect time" again...).

> Alternatively add (debug-on-entry 'scroll-lock-mode) near the beginning
> of your config and restart.  The backtrace should tell you what invoked
> the mode, you see which form in which file is currently processed etc.
> c to continue.  Then remove the `debug-on-entry' call.

Huh... that was weird...?

Looks like the command is run, but I swear it wasn't by me, at least not
intentionally:

Debugger entered--entering a function:
* scroll-lock-mode(toggle)
  funcall-interactively(scroll-lock-mode toggle)
  call-interactively(scroll-lock-mode nil nil)
  command-execute(scroll-lock-mode)


The command is bound to Scroll_lock.  But that is not a key on my
keyboard, nor one I press intentionally.

What I did to get that stack trace was to Alt-TAB to a different window
and back. Could it be that Alt-TAB is interpreted as Scroll_lock?

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Steinar Bang <sb@dod.no>:
>>>>> Michael Heerdegen <michael_heerdegen@web.de>:
>> Steinar Bang <sb@dod.no> writes:

>>> Now I just got to figure out what switches the behaviour on
>>> (i.e. it's ".emacs bisect time" again...).

>> Alternatively add (debug-on-entry 'scroll-lock-mode) near the
>> beginning of your config and restart.  The backtrace should tell you
>> what invoked the mode, you see which form in which file is currently
>> processed etc.  c to continue.  Then remove the `debug-on-entry'
>> call.

> Huh... that was weird...?

> Looks like the command is run, but I swear it wasn't by me, at least not
> intentionally:
[snip!]
> What I did to get that stack trace was to Alt-TAB to a different window
> and back. Could it be that Alt-TAB is interpreted as Scroll_lock?

The Alt-TAB between window is the culprit!

Every time I switch into an emacs window with Alt-TAB I toggle
scroll-lock-mode on or off.

Very annoying!

Why is a command bound to Scroll_lock run when Alt-TAB is pressed?

And how can I get rid of it?

Thanks!


- Steinar

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Steinar Bang <sb@dod.no>:
>>>>> Michael Heerdegen <michael_heerdegen@web.de>:
>>> Steinar Bang <sb@dod.no> writes:

>>>> Now I just got to figure out what switches the behaviour on
>>>> (i.e. it's ".emacs bisect time" again...).

>>> Alternatively add (debug-on-entry 'scroll-lock-mode) near the
>>> beginning of your config and restart.  The backtrace should tell you
>>> what invoked the mode, you see which form in which file is currently
>>> processed etc.  c to continue.  Then remove the `debug-on-entry'
>>> call.

>> Huh... that was weird...?

>> Looks like the command is run, but I swear it wasn't by me, at least not
>> intentionally:
> [snip!]
>> What I did to get that stack trace was to Alt-TAB to a different window
>> and back. Could it be that Alt-TAB is interpreted as Scroll_lock?

> The Alt-TAB between window is the culprit!

> Every time I switch into an emacs window with Alt-TAB I toggle
> scroll-lock-mode on or off.

Correction: it's not the Alt-TAB, it's the selection of the emacs window
that toggles scroll-lock mode on or off.

Even when I select an emacs window with the mouse cursor, it triggers
toggling of scroll-lock-mode.

But one question remains: how do I get rid of this behaviour?

Re: Annoying arrow key scroll behaviour in emacs 27

[Robert Pluim]

>>>>> On Wed, 01 Dec 2021 17:26:57 +0100, Steinar Bang <sb@dod.no> said:
    Steinar> Correction: it's not the Alt-TAB, it's the selection of the emacs window
    Steinar> that toggles scroll-lock mode on or off.

    Steinar> Even when I select an emacs window with the mouse cursor, it triggers
    Steinar> toggling of scroll-lock-mode.

    Steinar> But one question remains: how do I get rid of this behaviour?

What are the values of 'focus-in-hook', 'focus-out-hook', and
'after-focus-change-function'?

Robert
-- 

Re: Annoying arrow key scroll behaviour in emacs 27

[Michael Heerdegen]

Steinar Bang <sb@dod.no> writes:

> But one question remains: how do I get rid of this behaviour?

I have no idea.  Did you already check the lossage (C-h l) for a key
event that may be involved?

Does this also happen with emacs -Q?  With a different terminal?

If that doesn't get us anywhere then... it's indeed bisect time I think.


Michael.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Michael Heerdegen <michael_heerdegen@web.de>:
> Steinar Bang <sb@dod.no> writes:

> I have no idea.  Did you already check the lossage (C-h l) for a key
> event that may be involved?

Here's the bottom of the buffer that results from C-h l:
 ...
 <Scroll_Lock>             ;; scroll-lock-mode
 ;; handle-switch-frame
 <help-echo> <Scroll_Lock> ;; scroll-lock-mode
 <Scroll_Lock>             ;; scroll-lock-mode
 <Scroll_Lock>             ;; scroll-lock-mode
 <Scroll_Lock>             ;; scroll-lock-mode
 <Scroll_Lock>             ;; scroll-lock-mode
 C-h l                     ;; view-lossage


> Does this also happen with emacs -Q?

Yes.  It also toggles scroll-lock-mode when the emacs window is
selected.

> With a different terminal?

I don't use a terminal.  I use GUI Emacs through X11 forwarding in ssh.

I use MobaXTerm for this since the virus software on this machine has
decided to block cygwin X (it's a work machine where I don't control the
virus software.

> If that doesn't get us anywhere then... it's indeed bisect time I think.

Ah well.  Since "emacs -Q" also exhibits this behaviour then it's
probably not something in my config...?

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Robert Pluim <rpluim@gmail.com>:

> What are the values of 'focus-in-hook', 'focus-out-hook', and
> 'after-focus-change-function'?

In a regular emacs:

focus-in-hook is a variable defined in ‘frame.el’.
Its value is (flycheck-display-error-at-point-soon t)
Local in buffer index.js<bokbase.web.frontend/src/main/frontend/src>; global value is nil

focus-out-hook is a variable defined in ‘frame.el’.
Its value is (flycheck-cancel-error-display-error-at-point-timer t)
Local in buffer index.js<bokbase.web.frontend/src/main/frontend/src>; global value is nil

after-focus-change-function is a variable defined in ‘frame.el’.
Its value is
#f(advice-wrapper :after ignore blink-cursor--rescan-frames)


In "emacs -Q" (which also toggles scroll-lock-mode when the window is selected):

focus-in-hook is a variable defined in ‘frame.el’.
Its value is nil

focus-out-hook is a variable defined in ‘frame.el’.
Its value is nil

after-focus-change-function is a variable defined in ‘frame.el’.
Its value is
#f(advice-wrapper :after ignore blink-cursor--rescan-frames)

Re: Annoying arrow key scroll behaviour in emacs 27

[Eli Zaretskii]

> From: Steinar Bang <sb@dod.no>
> Date: Wed, 01 Dec 2021 20:13:53 +0100
> 
> Here's the bottom of the buffer that results from C-h l:
>  ...
>  <Scroll_Lock>             ;; scroll-lock-mode
>  ;; handle-switch-frame
>  <help-echo> <Scroll_Lock> ;; scroll-lock-mode
>  <Scroll_Lock>             ;; scroll-lock-mode
>  <Scroll_Lock>             ;; scroll-lock-mode
>  <Scroll_Lock>             ;; scroll-lock-mode
>  <Scroll_Lock>             ;; scroll-lock-mode
>  C-h l                     ;; view-lossage
> 
> 
> > Does this also happen with emacs -Q?
> 
> Yes.  It also toggles scroll-lock-mode when the emacs window is
> selected.
> 
> > With a different terminal?
> 
> I don't use a terminal.  I use GUI Emacs through X11 forwarding in ssh.
> 
> I use MobaXTerm for this since the virus software on this machine has
> decided to block cygwin X (it's a work machine where I don't control the
> virus software.

Did you look at the configuration of MobaXTerm, whatever that is?
Maybe it is it that produces those Scroll_Lock keypresses, for some
reason?

If you cannot figure this out, just rebind Scroll_Lock 'ignore.

Re: Annoying arrow key scroll behaviour in emacs 27

[Michael Heerdegen]

Steinar Bang <sb@dod.no> writes:

> >>>>> Robert Pluim <rpluim@gmail.com>:
>
> > What are the values of 'focus-in-hook', 'focus-out-hook', and
> > 'after-focus-change-function'?
>
> In a regular emacs: [...]

So this can't be the culprit.  Let's better continue with Eli's advice.

Michael.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Eli Zaretskii <eliz@gnu.org>:

> Did you look at the configuration of MobaXTerm,

As far as I've been able to.  Scroll_lock doesn't figure any place in
the keyboard config I've seen.

I've also googled all angles I could think about with MobaXTerm and key
events, without finding anything useful.

> whatever that is?

It's a Windows X11 server combined with a terminal app with putty
compatible SSH support, and built in X11 SSH tunneling as well as a lot
of other stuff I haven't stumbled over yet.

It's a commercial program, but has a free-as-in-gratis version for
personal usage.

I use MobaXTerm, because a virus checker, over which I have no control,
has taken a dislike to cygwin X11, and the other X11 server I have been
using, XMing, went commercial in 2019.

For the most part MobaXTerm has worked well, and been more stable than
cygwin X.

This scroll-lock issue is the first strange behaviour I have seen.

> Maybe it is it that produces those Scroll_Lock keypresses, for some
> reason?

Yes, it seems likely.  But I have no idea how to verify that this is the
case.

> If you cannot figure this out, just rebind Scroll_Lock 'ignore.

Hm... like so?
 (global-set-key [Scroll_lock] 'ignore)

I tried that in .emacs.  Emacs doesn't fail on start, but it didn't help
either.  Emacs started with that setting, still toggles scroll-lock-mode
every time I select the window.

Thanks!


- Steinar

Re: Annoying arrow key scroll behaviour in emacs 27

[Michael Heerdegen]

Steinar Bang <sb@dod.no> writes:


> Hm... like so?
>  (global-set-key [Scroll_lock] 'ignore)
                           ^
[Scroll_Lock] maybe?

Michael.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Michael Heerdegen <michael_heerdegen@web.de>:

> Steinar Bang <sb@dod.no> writes:
>> Hm... like so?
>> (global-set-key [Scroll_lock] 'ignore)
>                            ^
> [Scroll_Lock] maybe?

Yep!  This worked:
(global-set-key [Scroll_Lock] 'ignore)

Finally no more scroll-lock toggling on entering an emacs window.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Steinar Bang <sb@dod.no>:
>>>>> Michael Heerdegen <michael_heerdegen@web.de>:

>> Steinar Bang <sb@dod.no> writes:
>>> Hm... like so?
>>> (global-set-key [Scroll_lock] 'ignore)
>> ^
>> [Scroll_Lock] maybe?

> Yep!  This worked:
> (global-set-key [Scroll_Lock] 'ignore)

> Finally no more scroll-lock toggling on entering an emacs window.

Just did a check without the config, on an emacs displayed natively in
the X11 server on the debian machine I've been running the emacs on, and
on the natvie X11 server, emacs does not toggle scroll-lock-mode when a
window is selected.

That machine's keyboard has a Scroll_lock key, and that key toggles the
scroll-lock-mode, or... at least it does so until the new config is in
place.

But scroll-lock-mode is something I've never thought about or wanted, so
I don't think I will miss it...:-)

Re: Annoying arrow key scroll behaviour in emacs 27

[Michael Heerdegen]

Steinar Bang <sb@dod.no> writes:

> But scroll-lock-mode is something I've never thought about or wanted, so
> I don't think I will miss it...:-)

And even if you change your mind, M-x scroll-lock-mode will still be
functional.

But I wonder if other programs do receive these scroll-lock key hits,
too.

Michael.

Re: Annoying arrow key scroll behaviour in emacs 27

[Eli Zaretskii]

> From: Steinar Bang <sb@dod.no>
> Date: Thu, 02 Dec 2021 18:21:05 +0100
> 
> > If you cannot figure this out, just rebind Scroll_Lock 'ignore.
> 
> Hm... like so?
>  (global-set-key [Scroll_lock] 'ignore)

Is it Scroll_lock or something else?  The name is important.

> I tried that in .emacs.  Emacs doesn't fail on start, but it didn't help
> either.  Emacs started with that setting, still toggles scroll-lock-mode
> every time I select the window.

Then set debug-on-entry to trigger a debugger when scroll-lock-mode is
invoked, and see what does that.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Eli Zaretskii <eliz@gnu.org>:

>> Hm... like so?
>> (global-set-key [Scroll_lock] 'ignore)

> Is it Scroll_lock or something else?  The name is important.

It was Scroll_Lock (with a capital L), and with this, it works:
 (global-set-key [Scroll_Lock] 'ignore)

Re: Annoying arrow key scroll behaviour in emacs 27

[Eli Zaretskii]

> From: Steinar Bang <sb@dod.no>
> Date: Thu, 02 Dec 2021 18:53:34 +0100
> 
> Just did a check without the config, on an emacs displayed natively in
> the X11 server on the debian machine I've been running the emacs on, and
> on the natvie X11 server, emacs does not toggle scroll-lock-mode when a
> window is selected.

Of course.  Emacs doesn't do any such silly things.

Re: Annoying arrow key scroll behaviour in emacs 27

[Steinar Bang]

>>>>> Eli Zaretskii <eliz@gnu.org>:

>> Just did a check without the config, on an emacs displayed natively in
>> the X11 server on the debian machine I've been running the emacs on, and
>> on the natvie X11 server, emacs does not toggle scroll-lock-mode when a
>> window is selected.

> Of course.  Emacs doesn't do any such silly things.

(I thought it was better to actually test, than assume)