diff --git a/share/qtcreator/qmldesigner/propertyEditorQmlSources/QtQuick/RectangleSpecifics.qml b/share/qtcreator/qmldesigner/propertyEditorQmlSources/QtQuick/RectangleSpecifics.qml
index f5d0b6ec017..e37fb4c1df8 100644
--- a/share/qtcreator/qmldesigner/propertyEditorQmlSources/QtQuick/RectangleSpecifics.qml
+++ b/share/qtcreator/qmldesigner/propertyEditorQmlSources/QtQuick/RectangleSpecifics.qml
@@ -78,7 +78,7 @@ Column {
 
     CornerRadiusSection {
         id: cornerRadiusSection
-        property bool radiiAvailable: backendValues.topLeftRadius.isAvailable
+        property bool radiiAvailable: backendValues.topLeftRadius?.isAvailable ?? false
                                 // && backendValues.topRightRadius.isAvailable
                                 // && backendValues.bottomLeftRadius.isAvailable
                                 // && backendValues.bottomRightRadius.isAvailable