diff --git a/styleplugins/chameleon/chameleonstyle.cpp b/styleplugins/chameleon/chameleonstyle.cpp
index 6814613..8339585 100644
--- a/styleplugins/chameleon/chameleonstyle.cpp
+++ b/styleplugins/chameleon/chameleonstyle.cpp
@@ -4354,11 +4354,13 @@ void ChameleonStyle::polish(QWidget *w)
                 handle.setEnableBlurWindow(true);
 
                 DPlatformTheme *theme = DGuiApplicationHelper::instance()->applicationTheme();
-                setWindowRadius(w, qMax(0, qMin(theme->windowRadius(), 18)));
+                if (theme->isValid()) {
+                    setWindowRadius(w, qMax(0, qMin(theme->windowRadius(), 18)));
+                    connect(theme, &DPlatformTheme::windowRadiusChanged, w, [w](int r){
+                       setWindowRadius(w, qMax(0, qMin(r, 18)));
+                    });
+                }
 
-                connect(theme, &DPlatformTheme::windowRadiusChanged, w, [w](int r){
-                   setWindowRadius(w, qMax(0, qMin(r, 18)));
-                });
                 w->setAttribute(Qt::WA_TranslucentBackground);
                 connect(DWindowManagerHelper::instance(), SIGNAL(hasCompositeChanged()), w, SLOT(update()));
             }