Created attachment 157797 [details]
Qt5/KF5 Libreoffice plugin with Breeze Application style. Note the lack of indication that "Cell Value" is selected.

SUMMARY

Dropdown boxes in LibreOffice show no indication that they are selected using the Breeze Application Style and the KF5/Qt 5 plugins.

STEPS TO REPRODUCE
1. Ensure Breeze is your Application Style. In LibreOffice Calc, open a new document and navigate to Format -> Conditional -> Condition. By default, the box under to "Condition 1" is selected and lists "Cell value". You could also navigate to Data -> Sort and observe the box next to "Column".

OBSERVED RESULT:
There is no indication that the active dropdown box is the selected box (ie, the box that your keyboard interacts with if you use the up/down arrow keys).

EXPECTED RESULT:
There should be a border (matching the system's accent color) around the box or some other indication that it is currently selected, similar to the one you get if you hover your the mouse over the box. If you use the GTK3 plugin or another Application Style with the Qt5/KF5 plugins (example: Oxygen), this works as expected, but it is missing when using the KF5/Qt 5 plugin with the Breeze theme. Pictures are attached showing the difference between the GTK3 plugin and Qt5/KF5 plugins.

Operating System: Debian GNU/Linux 12
KDE Plasma Version: 5.27.2
KDE Frameworks Version: 5.103.0
Qt Version: 5.15.8
Kernel Version: 6.1.0-7-amd64 (64-bit)
Graphics Platform: X11

LibreOffice version:

Version: 7.4.5.1 / LibreOffice Community
Build ID: 40(Build:1)
CPU threads: 6; OS: Linux 6.1; UI render: default; VCL: kf5 (cairo+xcb)
Locale: en-US (en_US.UTF-8); UI: en-US
Debian package version: 4:7.4.5-2
Calc: threaded