Problem
Since Fedora 40, applications using the GTK4 toolkit are displayed incorrectly in VirtualBox when 3D acceleration passthrough is enabled. The applications are often completely broken, showing just colored rectangles and various artifacts. Additionally, the Fedora installer (anaconda) displays incorrectly in a different way, with text corruption and incorrect colors.
Example:
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Cause
The GTK4 application rendering issues appear to be linked to the new NGL renderer used in GTK4 applications and the 3D passthrough functionality in VirtualBox. The cause of the anaconda rendering issue is not yet known.
Related Issues
Bugzilla: 2274930 – GTK4 apps render badly on VirtualBox with 3D acceleration passthrough enabled
Bugzilla: 2276102 – Severe graphical corruption in anaconda (Fedora installer) when running on VirtualBox with 3D passthrough enabled
GTK: ngl: Apps are displaying glitchy on VirtualBox (#6542) · Issues · GNOME / gtk · GitLab
Mesa: Issues rendering gtk4 windows on VirtualBox with 3D acceleration on Fedora-40/mesa-24.0.5 (#11008) · Issues · Mesa / mesa · GitLab
Workarounds
As a workaround, disable 3D acceleration passthrough in VirtualBox until the underlying issue is resolved. If you encounter problems using the default “VMSVGA” video adapter with 3D passthrough disabled, use the “VBoxSVGA” adapter instead (still with 3D passthrough disabled).