diff --git a/src/Mod/Sketcher/Gui/PropertyConstraintListItem.cpp b/src/Mod/Sketcher/Gui/PropertyConstraintListItem.cpp
index d9cd6ae72d..88149dbcc5 100644
--- a/src/Mod/Sketcher/Gui/PropertyConstraintListItem.cpp
+++ b/src/Mod/Sketcher/Gui/PropertyConstraintListItem.cpp
@@ -201,7 +201,7 @@ void PropertyConstraintListItem::assignProperty(const App::Property* prop)
             else {
                 // search inside this item
                 if (namedIndex < numNamed) {
-                    child = dynamic_cast<PropertyUnitItem*>(this->child(namedIndex));
+                    child = qobject_cast<PropertyUnitItem*>(this->child(namedIndex));
                 }
 
                 if (!child) {