Bug 486766

Summary: Gtk-WARNING **: GtkGizmo 0x6127b629ff10 (slider) reported min height -2, but sizes must be >= 0
Product: [Plasma] Breeze Reporter: Benjamin Hennion <benjamin.hennion>
Component: gtk themeAssignee: Plasma Bugs List <plasma-bugs-null>
Status: REPORTED ---    
Severity: normal CC: agrinev98, benjamin.hennion, uhhadd
Priority: NOR    
Version First Reported In: 6.0.2   
Target Milestone: ---   
Platform: Arch Linux   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: UI file with Scrollbar

Description Benjamin Hennion 2024-05-08 06:58:21 UTC
Created attachment 169293 [details]
UI file with Scrollbar

SUMMARY
Whenever a GtkScrollbar is displayed, the terminal outputs:

> Gtk-WARNING **: 08:38:04.284: GtkGizmo 0x6127b629ff10 (slider) reported min height -2, but sizes must be >= 0

This does not happen with GTK_THEME=adwaita, so it is most likely a breeze-gtk issue.
See also https://gitlab.gnome.org/GNOME/gtk/-/issues/4446 which suggests such issues are CSS-related.

STEPS TO REPRODUCE
1. Download the attached gizmo.ui. It contains a GtkWindow with a GtkScrollbar. 
2. Open it via `gtk4-builder-tool preview gizmo.ui` (with breeze as gtk theme in KCM)
3. See the warnings in the terminal output.
4. Try again with `GTK_THEME=adwaita gtk4-builder-tool preview gizmo.ui`. No warnings.

OBSERVED RESULT
> Gtk-WARNING **: 08:38:04.284: GtkGizmo 0x6127b629ff10 (slider) reported min height -2, but sizes must be >= 0

EXPECTED RESULT
No warning