Menu bar missing or HiDPI scaling incorrect under KDE

Fieronymus · August 26, 2025, 12:34pm

Hello everyone,

I have two problems with LibreOffice under Arch/Nvidia-Open/Plasma/Wayland:

HiDPI scaling is correct when I use QT_QPA_PLATFORM=xcb, but then the menu bar disappears after I save a document, for example.
The menu bar is visible when I use SAL_USE_VCLPLUGIN=gtk3 or SAL_USE_VCLPLUGIN=kf5, but then the HiDPI scaling is incorrect.

The workarounds mentioned so far work individually, but not together. Does anyone else have both problems and know how to deal with them?
This scaling issue has been bothering me for several years, and the menu bar issue has been bothering me since I started using a top status bar/global menu, which is where LO also places its menu.

Pakete installiert:

local/libreoffice-fresh 25.8.0-1
    LibreOffice branch which contains new features and program enhancements
local/libreoffice-fresh-de 25.8.0-1
    German language pack for LibreOffice Fresh

Kind regards
and thanks in advance

nanozoon · August 26, 2025, 4:38pm

You are experiencing two overlapping issues in LibreOffice on Arch Linux with Nvidia-Open and Plasma/Wayland:

When using
```
QT_QPA_PLATFORM=xcb
```
→ the HiDPI scaling is set correctly, but the menu bar disappears after saving (or upon some other event).
When using
```
SAL_USE_VCLPLUGIN=gtk3
```
or
```
SAL_USE_VCLPLUGIN=kf5
```
→ the menu bar is visible, but the HiDPI scaling is incorrect.
That is, each solution addresses only one issue and breaks the other.

Some possible solutions:

1. Using VCL Qt/KDE with forced manual DPI scaling:

SAL_USE_VCLPLUGIN=kf5 QT_SCALE_FACTOR=2 libreoffice

(Switch the number to suit your screen resolution).
This adjusts the HiDPI while maintaining the integrity of the menus in the Plasma environment.
2. Try LibreOffice’s internal DPI variable:
Open LibreOffice → Tools → Options → View.
There are Scaling or Icon size settings. Try increasing them manually; this circumvents the HiDPI issue in the GTK/Qt interface.
3. Use Wayland directly instead of XCB:

SAL_USE_VCLPLUGIN=kf5 QT_QPA_PLATFORM=wayland libreoffice

In some cases this solves missing menu bar issues and improves HiDPI behavior.
4. Check the global menu in Plasma:
Sometimes the missing menu bar is related to LibreOffice’s integration with the Plasma appmenu.
Try temporarily disabling the global menu to see if it’s the problem, or replacing it with the “Application Titlebar.”
5. Patchwork solution (GTK3 scaling):

GDK_SCALE=2 GDK_DPI_SCALE=0.5 SAL_USE_VCLPLUGIN=gtk3 libreoffice

This manually adjusts the scale.

❖ Since you’re on Arch/Plasma/Wayland, the most likely solution is:

SAL_USE_VCLPLUGIN=kf5 QT_QPA_PLATFORM=wayland QT_SCALE_FACTOR=2 libreoffice

because it balances the correct HiDPI and visible menus.

Also, I’m not an expert on Arch Linux, so try these solutions if they work, or wait for a specialist to give you a better solution.

Fieronymus · August 27, 2025, 8:17am

Thanks for answering and thinking about; but unfortunately no desired outcome.

The problem persists with either of these environment variables. I just can’t have it auto-scaled properly on both screens