GUI is different when started via launcher or by double-clicking on .tex-file

Environment

• TeXstudio: TeXstudio 4.5.1 (git 0.0.0++)
• Qt: Nutze Qt-Version 6.5.0, kompiliert mit Qt 6.4.2 R
• OS: Arch Linux (linux 6.2.10.arch1-1)
• TeX distribution: texlive-core 2023.66587-2

Additional info... maybe it can be helpful (that's what I hope): $ pacman -Q xfwm4 xfwm4 4.18.0-1 $ pacman -Q qt5-base qt5-base 5.15.9+kde+r151-1 $ pacman -Q gtk4 gtk4 1:4.10.1-2 $ pacman -Q gtk3 gtk3 1:3.24.37-1

Expected behavior

When I start up TeXstudio either by

1. double-clicking on a .tex-file or
2. starting the program via a launcher, such as albert or XFCE's built-in app-finder, I expect it to look like

Or more succinct: Regardless of the startup method, I expect TeXstudio to always have the same look.

Actual behavior

The actual behavior is that TeXstudio seems to have a different GUI style when started

1. by using a launcher: the buttons look slightly different and the document styling and
2. by double-clicking on a .tex-file: it's the usual/"old" style.

About the layout when started via launcher:

A video: https://user-images.githubusercontent.com/6051516/231719366-cc3a924e-008c-4056-801e-2773e0c39c92.mp4

How to reproduce

Start TeXstudio via launcher or by double-clicking on a .tex-file.