Merge branch 'workaround_kde_qqc2_crash' of https://github.com/StefanBruens/Cura into StefanBruens-workaround_kde_qqc2_crash

cura_app.py

@@ -226,6 +226,12 @@ if Platform.isLinux() and getattr(sys, "frozen", False):
     import trimesh.exchange.load
     os.environ["LD_LIBRARY_PATH"] = old_env
 
+# WORKAROUND: Cura#5488
+# When using the KDE qqc2-desktop-style, the UI layout is completely broken, and
+# even worse, it crashes when switching to the "Preview" pane.
+if Platform.isLinux():
+    os.environ["QT_QUICK_CONTROLS_STYLE"] = "default"
+    
 if ApplicationMetadata.CuraDebugMode:
     ssl_conf = QSslConfiguration.defaultConfiguration()
     ssl_conf.setPeerVerifyMode(QSslSocket.VerifyNone)