Environment
Kvantum: 1.1.8
Qt6: 6.11.1
Qt5: 5.15.19+kde+r96
KDE Plasma: 6.7.3
KWin: 6.7.3
Distribution: Arch Linux
Description
When using Kvantum as the Qt style, all popup windows (QMenu, context menus, combo box popups, etc.) are displayed without window shadows.
Normal application windows have shadows as expected.
The issue occurs with all Kvantum themes that I tested, including the default themes.
Steps to reproduce
Select Kvantum as the Qt application style.
Start a Qt6 application (for example Dolphin).
Open a context menu or a combo box.
Expected behavior
Popup menus should have the same compositor window shadows as when using the Breeze style.
Actual behavior
Popup menus have no window shadows at all.
Additional information
The problem occurs under both Wayland and X11/XWayland.
Switching to Breeze immediately restores popup shadows.
Therefore, the compositor (KWin) appears to work correctly.
The following command restores the expected behavior:
QT_STYLE_OVERRIDE=Breeze dolphin
With:
QT_STYLE_OVERRIDE=kvantum dolphin
popup shadows are missing again.
The Kvantum configuration contains:
shadowless_popup=false
so popup shadows are not intentionally disabled.
This seems independent of the selected Kvantum theme.
Please let me know if additional debug output or logging would be useful