Bug 505220

I've installed Gentoo on a new hardware, so it's a new installation of KDevelop. I want to start a new C Tutorial Project. So i click on "new project". I can't find something i want to have so i click on the button "Mehr Vorlagen herunterladen", it's the german version of something like "download more templates". If i click on this button, KDevelop closes the "New Project" Window, goes back to the main Interface and i can't start anything nor klick on a button / menu. When i use the terminal to start KDevelop i have this output when i click on the button:
"file:///usr/lib64/qt6/qml/org/kde/kirigami/templates/private/DrawerHandle.qml:117:5: TypeError: Cannot read property ‘width’ of null""

So i have used emerge to see what versions i got installed:
[ebuild R ] kde-frameworks/kirigami-6.13.0:6/6.13::gentoo USE=“examples openmp -debug -test” 0 KiB
[ebuild R ] dev-util/kdevelop-24.12.3:6/24.12::gentoo USE=“gdbui handbook plasma qmake share subversion -debug -test” LLVM_SLOT=“19 -15 -16 -17 -18” 0 KiB
[ebuild R ] dev-libs/kirigami-addons-1.7.0:6::gentoo USE=“-debug -doc -test” 0 KiB
And also Qt 6.8.3

I use the Menu "Help" -> "About KDevelop" for this Informations:
KDevelop: 6.1.241203 (24.12.3)
KDE Frameworks: 6.13.0
Qt: 6.8.3 wird verwendet und gebaut wurde mit 6.8.3
Gentoo Linux (Wayland)
Build ABI: x86_64-little_endian-lp64
Kernel: linux 6.12.16-gentoo-x86_64

English is not my native language and i've tried to be as specific as possible, if you need something else please let me know.