[Lazarus] 1 keypress gives multiple letters ONLY in program written in Lazarus in raspbian jessie Pi 2

[Dennis]

In the past, the same program (written in lazarus ) running in the same
hardware pi 2 under the older raspbian version has NO PROBLEM.

But the SD Card was corrupted so I installed the latest raspbian OS
jessie on the same Pi 2 on a new SD Card.
I reinstalled everything (e.g. mysql etc) and my program and it runs
fine EXCEPT that pressing a key once will gives multiple letters.
BUT this problem only occurs with my program. All other programs e.g.
web browser and file managers , text editor DO not have this problem.

I already set the Menu-> Preferences->Keyboard and Mouse->Keyboard->
Character Repeat->Repeat Delay to the maximum (1000 long)
but still does not help.

I cannot ask raspbian forum as they rarely write free pascal programs.

Can anyone think of what special things that lazarus GUI program uses
(e.g. QT, gtk ) that might not work with the new raspbian jessie?

Note: I have tried installing FPC 3.0 and latest lazarus on the pi 2
raspbian jessie and recompile the program but it has the same program.


Dennis

[Michael Thompson]

Post by Dennis
EXCEPT that pressing a key once will gives multiple letters.

We've had this before, under Ubuntu from memory.

Yup: http://bugs.freepascal.org/view.php?id=23140 (and related)

You may find some ideas in there.

Mike

[JuuS]

Post by Dennis
In the past, the same program (written in lazarus ) running in the same
hardware pi 2 under the older raspbian version has NO PROBLEM.
But the SD Card was corrupted so I installed the latest raspbian OS
jessie on the same Pi 2 on a new SD Card.
I reinstalled everything (e.g. mysql etc) and my program and it runs
fine EXCEPT that pressing a key once will gives multiple letters.
BUT this problem only occurs with my program.

Remote possibility: do you have ibus installed and running? If so try
"ibus exit".

Julius

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[Giuliano Colla]

Post by Dennis
But the SD Card was corrupted so I installed the latest raspbian OS
jessie on the same Pi 2 on a new SD Card.
I reinstalled everything (e.g. mysql etc) and my program and it runs
fine EXCEPT that pressing a key once will gives multiple letters.
BUT this problem only occurs with my program. All other programs
e.g. web browser and file managers , text editor DO not have this problem.

The villain could be some "input method" active.
Juus's suggestion is quite drastic, just kill the ibus service, which
handles input methods.
Keyboard input methods configuration (setting to "none") could do the
trick without killing all of the ibus services.

Giuliano

[JuuS]

Post by Giuliano Colla

Post by Dennis
But the SD Card was corrupted so I installed the latest raspbian OS
jessie on the same Pi 2 on a new SD Card.
I reinstalled everything (e.g. mysql etc) and my program and it runs
fine EXCEPT that pressing a key once will gives multiple letters.
BUT this problem only occurs with my program. All other programs
e.g. web browser and file managers , text editor DO not have this problem.

The villain could be some "input method" active.
Juus's suggestion is quite drastic, just kill the ibus service, which
handles input methods.

Hi, yes its drastic but I wanted to know if ibus was the culprit.

Personally I had quite a fight with ibus and I finally removed it from
my system with no ill effects. It is mostly used AFAIK with asian
"alphabets".

--

[m***@gmail.com]

Post by JuuS
Hi, yes its drastic but I wanted to know if ibus was the culprit.
Personally I had quite a fight with ibus and I finally removed it from
my system with no ill effects. It is mostly used AFAIK with asian
"alphabets".

i have the same Problem with PI 3 and mouseandkeyinput for a touchscreen
numpad.

I´ll try the solution and report.
But the occurrence of problem is very random.

--

[Giuliano Colla]

Post by JuuS
Personally I had quite a fight with ibus and I finally removed it from
my system with no ill effects. It is mostly used AFAIK with asian
"alphabets".

There must be some problem with ibus/input methods in the Debian line,
because it would appear that more or less all recent Debian based
distro's (Ubuntu, Raspbian, ect.) show some weird keyboard behaviour,
which wasn't present in the previous versions.

Red Hat line (Red Hat, Fedora, CentOs etc.) appears to be immune from
this problem. I didn't find any complaint of this type on Internet, and
when I have been forced to enable keyboard input methods to support
Chinese, nothing strange happened (except when if you forget to switch
back to English ;-) ...)

Maybe someone with a good knowledge of both worlds could find where the
problem is?

Giuliano


--

[Dennis]

Post by Giuliano Colla

Post by JuuS
Personally I had quite a fight with ibus and I finally removed it from
my system with no ill effects. It is mostly used AFAIK with asian
"alphabets".

There must be some problem with ibus/input methods in the Debian line,
because it would appear that more or less all recent Debian based
distro's (Ubuntu, Raspbian, ect.) show some weird keyboard behaviour,
which wasn't present in the previous versions.
Red Hat line (Red Hat, Fedora, CentOs etc.) appears to be immune from
this problem. I didn't find any complaint of this type on Internet,
and when I have been forced to enable keyboard input methods to
support Chinese, nothing strange happened (except when if you forget
to switch back to English ;-) ...)
Maybe someone with a good knowledge of both worlds could find where
the problem is?
Giuliano

I turned off Raspbian's Input Method and the problem is gone now.
thanks for everyone's tips.

Dennis

--

[Michael Thompson]

I know this issue is resolved, but I've just stumbled across this:

http://wiki.lazarus.freepascal.org/Lazarus_Faq#Typing_under_Ubuntu_in_edit_fields_generate_duplicate_letters

We'll need to change Ubuntu now to Linux in general, but before I do that:
Giuliano: Do you know if any of the steps listed here would have helped?
If not, can you let me know how you disabled the Input Manager, and I'll
update the wiki accordinly.

Thanks

Mike

Post by Dennis

Post by Giuliano Colla

Post by JuuS
Personally I had quite a fight with ibus and I finally removed it from
my system with no ill effects. It is mostly used AFAIK with asian
"alphabets".

There must be some problem with ibus/input methods in the Debian line,
because it would appear that more or less all recent Debian based distro's
(Ubuntu, Raspbian, ect.) show some weird keyboard behaviour, which wasn't
present in the previous versions.
Red Hat line (Red Hat, Fedora, CentOs etc.) appears to be immune from
this problem. I didn't find any complaint of this type on Internet, and
when I have been forced to enable keyboard input methods to support
Chinese, nothing strange happened (except when if you forget to switch back
to English ;-) ...)
Maybe someone with a good knowledge of both worlds could find where the
problem is?
Giuliano
I turned off Raspbian's Input Method and the problem is gone now.

thanks for everyone's tips.
Dennis
--
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[Giuliano Colla]

Post by Michael Thompson
Giuliano: Do you know if any of the steps listed here would have
helped? If not, can you let me know how you disabled the Input
Manager, and I'll update the wiki accordinly.

I have only hearsay knowledge, from this list complaints, and from some
search on Internet I made because of that.
I'm not using Ubuntu or any other Debian/Ubuntu derived distro, and I do
not have a direct experience.
I'm using the Red Hat distros line (RHEL, Fedora and CentOs) and I did
never stumble into a similar problem.
Therefore take what I say with appropriate caution (and most of all do
not use it in tribunal .)

However the problem appears to arise from the Keyboard Input Methods
being enabled by default, even when no actual Input Method is assigned.
From what I gathered, this problem popped up as with Ubuntu 11, and
should be related to Gnome Desktop.
Previous versions were immune, but I can't tell if it was because ibus
service wasn't used, or because Keyboard Input Methods were not enabled.

However the full picture is the following:

Input Methods are those methods which allow to accommodate languages
with ideographic symbols which cannot possibly fit in a normal sized
keyboard, such as Chinese.

Those user need also to enter Latin alphabet characters for system
commands, therefore a keyboard shortcut is required to toggle on and off
the Input Method.

The standard shortcut to toggle Input Method is ctrl-space, which
happens also to be the standard code completion shortcut of Lazarus.
This alone can be a cause of troubles.
Moreover, if the Input Methods are enabled, but no actual Input method
is defined, toggling may lead to weird results, such as characters being
entered twice, characters being lost etc.

The steps to overcome the problem are:

1) If Input Methods are required (e.g. a Chinese user), one of the two
shortcuts must be changed.

2) If no Input Methods are required, they should be disabled. No general
rule can be given on how to do that, because each Desktop environment
does it its way. Gnome provides in System Settings an "Input Method"
entry. KDE provides an Icon in the systray, but only if a specific Input
Method package has been installed, otherwise the Input Methods are disabled.

3) If no Input Methods are required and the user is unable to disable
the Input Methods, one can simply stop the ibus service, whose only
purpose appears to be that of supporting the Input Methds. Again, how to
do that is strongly system dependent.

I can't say if the steps indicated in the Wiki page are useful in
general. From what I read GTK_IM_MODULE=gtk-im-context-simple
should be a better choice than gtk-im-context-xim which enables the old
XIM (X Input Method) framework.
But it would require some testing in Ubuntu or Ubuntu siblings, and with
different locale.

That's all I can tell.

Giuliano


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[Giuliano Colla]

Post by Michael Thompson
http://wiki.lazarus.freepascal.org/Lazarus_Faq#Typing_under_Ubuntu_in_edit_fields_generate_duplicate_letters
We'll need to change Ubuntu now to Linux in general, but before I do
that: Giuliano: Do you know if any of the steps listed here would have
helped? If not, can you let me know how you disabled the Input
Manager, and I'll update the wiki accordinly.

I took the liberty of editing the Wiki entry, using all the information
I have.

Please feel free to adjust as you deem proper.

Giuliano


--

[Michael Thompson]

I took the liberty of editing the Wiki entry, using all the information I
have.
Please feel free to adjust as you deem proper.

Nice work. More technical than I was capable of :-)

Mike

[j***@misticnabica.hr]

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