diff --git a/lcl/interfaces/qt5/qtwscomctrls.pp b/lcl/interfaces/qt5/qtwscomctrls.pp
index 0bec6bb840..cb8abe9aa2 100644
--- a/lcl/interfaces/qt5/qtwscomctrls.pp
+++ b/lcl/interfaces/qt5/qtwscomctrls.pp
@@ -894,7 +894,8 @@ begin
     exit;
 
   QtTreeWidget := TQtTreeWidget(ALV.Handle);
-  if Assigned(QtTreeWidget) then
+  if Assigned(QtTreeWidget) and
+    not (csDesigning in ALV.ComponentState) then
   begin
     if ASortIndicator = siNone then
       QtTreeWidget.Header.SetSortIndicatorVisible(false)
diff --git a/lcl/interfaces/qt6/qtwscomctrls.pp b/lcl/interfaces/qt6/qtwscomctrls.pp
index 931c4bc8bd..07fbe86785 100644
--- a/lcl/interfaces/qt6/qtwscomctrls.pp
+++ b/lcl/interfaces/qt6/qtwscomctrls.pp
@@ -892,7 +892,8 @@ begin
     exit;
 
   QtTreeWidget := TQtTreeWidget(ALV.Handle);
-  if Assigned(QtTreeWidget) then
+  if Assigned(QtTreeWidget) and
+    not (csDesigning in ALV.ComponentState) then
   begin
     if ASortIndicator = siNone then
       QtTreeWidget.Header.SetSortIndicatorVisible(false)