Bug 167780 - Ctrl+Shift+U for entering Unicode chars doesn't work in LibreOffice
Summary: Ctrl+Shift+U for entering Unicode chars doesn't work in LibreOffice
Status: RESOLVED NOTOURBUG
Alias: None
Product: LibreOffice
Classification: Unclassified
Component: LibreOffice (show other bugs)
Version:
(earliest affected)
25.2.5.2 release
Hardware: All Linux (All)
: medium normal
Assignee: Not Assigned
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: KDE, KF5
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Reported: 2025-08-02 16:00 UTC by luc
Modified: 2025-08-04 22:19 UTC (History)
2 users (show)

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Crash report or crash signature:


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Description luc 2025-08-02 16:00:17 UTC
Description:
I often need Ctrl+Shift+U for entering certain characters that don't exist on my Estonian keyboard, e.g. ß in German or ê and ç in French. This works everywhere in Ubuntu (where Unicode input is supported). It also worked in LO for many years, but some versions ago it stopped working. 

I verified in Tools → Customize → Keyboard that there is no function assigned to CTRL+SHIFT+U. I know the Alt+X trick, which brings some relief. But it’s not a solution. CTRL+SHIFT+U is an important feature in Ubuntu and Debian, equivalent to the Alt+NUMKEY on MS-Windows. This input method provided by the OS is kind of disabled in LO. Not having it working in LO is a show stopper for those who need this feature.

Steps to Reproduce:
1. Open a new document or calc sheet.
2. Hit CTRL+SHIFT+U, an underlined "u" appears.  
3. Type "d", "f" followed by ENTER or SPACE


Actual Results:
The underlined "u" doesn't appear and instead it inserts the "d" and "f" characters.

Expected Results:
The unicode "ß" (\u+00df) should appear.


Reproducible: Always


User Profile Reset: Yes

Additional Info:
Version: 25.2.5.2 (X86_64) / LibreOffice Community
Build ID: 520(Build:2)
CPU threads: 12; OS: Linux 6.11; UI render: default; VCL: kf6 (cairo+xcb)
Locale: en-GB (en_GB.UTF-8); UI: en-US
Debian package version: 4:25.2.5-0tux1
Calc: threaded

My computer runs TUXEDO OS, a variant of Ubuntu 24.04 optimized for Tuxedo hardware. https://www.tuxedocomputers.com/en/TUXEDO-OS_1.tuxedo

$ lsb_release -a
No LSB modules are available.
Distributor ID: Tuxedo
Description:    TUXEDO OS
Release:        24.04
Codename:       noble
Comment 1 V Stuart Foote 2025-08-02 16:54:18 UTC
Behavior of dead keys are os/DE specific.

But in LibreOffice, should work cross platform using just U+00df and <Alt>+X to convert. Just set the font for the resulting glyph to a font with coverage of the Unicode.
Comment 2 Mike Kaganski 2025-08-02 18:07:13 UTC
https://gitlab.freedesktop.org/xorg/lib/libx11/-/issues/9

I see no problem when using GTK integration. But with kf6, I wonder how can it work at all, until the DE or input method implement it. IMO => NOTOURBUG.
Comment 3 luc 2025-08-02 21:33:21 UTC
The Alt+X trick is a nice workaround, but it's too complicated for typing a French text, and this silly detail makes me avoid using LO as an end user. I understand that it's an input method and LO itself is theoretically innocent, but Ctrl+Shift+U works in all applications on my computer, it works in Thunderbird, in Firefox, in Pulsar, even in a Gimp text area. Only in LO it doesn't.
Comment 4 Mike Kaganski 2025-08-03 05:37:59 UTC
(In reply to luc from comment #3)
> I understand that it's an input method and LO itself is theoretically
> innocent, but Ctrl+Shift+U works in all applications on my computer, it
> works in Thunderbird, in Firefox, in Pulsar, even in a Gimp text area. Only
> in LO it doesn't.

I don't know what Pulsar is (a CLI security-related demon?); but Gimp is built on (and actually created initially) GTK; and as far as I understand (and what I read), Mozilla TB & FF also use GTK. But LibreOffice has plugins for different DEs; and it can use GTK (on Gnome) of kf5/6 (on KDE); and on your desktop environment, which is KDE, it uses kf6.

And it *seems* to me, that it's not "Ctrl+Shift+U works in all applications on my computer", but rather "I have KDE, but only use the key combination with apps that are not KDE; and it naturally fails on the app that is *better* integrated with the DE of my choice".

But you can also force another plugin in LibreOffice; e.g., you may run it once using a command line like

> SAL_USE_VCLPLUGIN=gtk3 libreoffice

or have the environment variable exported from one of your startup scripts.

The gtk plugin may not be installed yet on your system; then it needs to be installed (see e.g. the normal Ubuntu way to do that, when you used apt to install LibreOffice (as opposed e.g. to snap): `apt-get install libreoffice-gtk3` - no idea if there's some difference in your derivative).

Please test if that makes a difference. Also check if the changed look-and-feel of LibreOffice with that plugin - there *will* be a change in look and feel - is OK for you, and maybe if it matches the look and feel of Gimp and friends...
Comment 5 Michael Weghorn 2025-08-04 07:35:28 UTC
(In reply to Mike Kaganski from comment #4)
> And it *seems* to me, that it's not "Ctrl+Shift+U works in all applications
> on my computer", but rather "I have KDE, but only use the key combination
> with apps that are not KDE; and it naturally fails on the app that is
> *better* integrated with the DE of my choice".
> 
> But you can also force another plugin in LibreOffice; e.g., you may run it
> once using a command line like
> 
> > SAL_USE_VCLPLUGIN=gtk3 libreoffice
> 
> or have the environment variable exported from one of your startup scripts.

I can confirm that.

I'm also running KDE Plasma and Ctrl+Shift+U works for GTK applications (e.g. Gedit) but not Qt applications (e.g. Kate).

Please see the discussion at https://bugs.kde.org/show_bug.cgi?id=103788 for more background and feel free to contribute there or in the Qt issue tracker, but this is something outside of LibreOffice's responsibility.
Comment 6 luc 2025-08-04 08:41:53 UTC
Thanks for these clarifications! 
NB With Pulsar I referred to https://pulsar-edit.dev
Comment 7 Mike Kaganski 2025-08-04 12:33:49 UTC
Note: there is libreoffice-gnome package in Debian [1]; it is separate from gtk2/gtk3; and it "contains the GIO support" (installs ucpgio1 library). If I understand correctly, the support of the key shortcut comes from GIO; and that *might* mean, that simply installing that package *could* maybe resolve your problem, without having to change the GUI plugin, and therefore without sacrificing the DE integration.

Would be great if you try and report back.

[1] https://packages.debian.org/bullseye/libreoffice-gnome
Comment 8 luc 2025-08-04 13:13:45 UTC
I installed it (see console log below), but Ctrl+Shift+U still didn't work.

$ sudo apt install libreoffice-gnome
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  gstreamer1.0-gtk3 libreoffice-gtk3 libreoffice-style-elementary
Suggested packages:
  libreoffice-evolution seahorse libreofficekit-data
The following NEW packages will be installed
  gstreamer1.0-gtk3 libreoffice-gnome libreoffice-gtk3 libreoffice-style-elementary
0 to upgrade, 4 to newly install, 0 to remove and 0 not to upgrade.
Need to get 8 958 kB of archives.
After this operation, 13,0 MB of additional disk space will be used.
Do you want to continue? [Y/n]
Get:1 https://txos.tuxedocomputers.com/ubuntu-plasma noble-updates/main amd64 libreoffice-gnome amd64 4:25.2.5-0tux1 [112 kB]
Get:2 https://mirrors.tuxedocomputers.com/ubuntu/mirror/archive.ubuntu.com/ubuntu noble-updates/main amd64 gstreamer1.0-gtk3 amd64 1.24.2-1ubuntu1.1 [35,5 kB]
Get:3 https://txos.tuxedocomputers.com/ubuntu-plasma noble-updates/main amd64 libreoffice-gtk3 amd64 4:25.2.5-0tux1 [574 kB]
Get:4 https://txos.tuxedocomputers.com/ubuntu-plasma noble-updates/main amd64 libreoffice-style-elementary all 4:25.2.5-0tux1 [8 237 kB]
Fetched 8 958 kB in 5s (1 969 kB/s)
Selecting previously unselected package libreoffice-gnome.
(Reading database ... 419054 files and directories currently installed.)
Preparing to unpack .../libreoffice-gnome_4%3a25.2.5-0tux1_amd64.deb ...
Unpacking libreoffice-gnome (4:25.2.5-0tux1) ...
Selecting previously unselected package gstreamer1.0-gtk3:amd64.
Preparing to unpack .../gstreamer1.0-gtk3_1.24.2-1ubuntu1.1_amd64.deb ...
Unpacking gstreamer1.0-gtk3:amd64 (1.24.2-1ubuntu1.1) ...
Selecting previously unselected package libreoffice-gtk3.
Preparing to unpack .../libreoffice-gtk3_4%3a25.2.5-0tux1_amd64.deb ...
Unpacking libreoffice-gtk3 (4:25.2.5-0tux1) ...
Selecting previously unselected package libreoffice-style-elementary.
Preparing to unpack .../libreoffice-style-elementary_4%3a25.2.5-0tux1_all.deb ...
Unpacking libreoffice-style-elementary (4:25.2.5-0tux1) ...
Setting up libreoffice-style-elementary (4:25.2.5-0tux1) ...
Setting up libreoffice-gtk3 (4:25.2.5-0tux1) ...
Setting up gstreamer1.0-gtk3:amd64 (1.24.2-1ubuntu1.1) ...
Setting up libreoffice-gnome (4:25.2.5-0tux1) ...
Processing triggers for libreoffice-common (4:25.2.5-0tux1) ...
$
Comment 9 Michael Weghorn 2025-08-04 13:54:59 UTC
(In reply to luc from comment #8)
> I installed it (see console log below), but Ctrl+Shift+U still didn't work.

Same here. But forcing the gtk3 VCL plugin to use the GTK based variant of LibreOffice (as Mike described earlier) makes it work:

    SAL_USE_VCLPLUGIN=gtk3 libreoffice --writer
Comment 10 luc 2025-08-04 22:19:41 UTC
Yes, that's it! SAL_USE_VCLPLUGIN=gtk3 didn't work for me because I hadn't libreoffice-gnome installed. So here is how I fixed my issue:

- sudo apt install libreoffice-gnome

- Open the LO Writer entry in the KDE Menu editor and add 

   SAL_USE_VCLPLUGIN=gtk3

  in the Environment field