diff --git a/components/zeosdbo/src/component/ZAbstractRODataset.pas b/components/zeosdbo/src/component/ZAbstractRODataset.pas
index 7af6dfa3..aa8821ae 100644
--- a/components/zeosdbo/src/component/ZAbstractRODataset.pas
+++ b/components/zeosdbo/src/component/ZAbstractRODataset.pas
@@ -274,9 +274,6 @@ type
     procedure InternalDelete; override;
     procedure InternalPost; override;
 
-    procedure SetFieldData(Field: TField; Buffer: Pointer;
-      NativeFormat: Boolean); override;
-    procedure SetFieldData(Field: TField; Buffer: Pointer); override;
     procedure DefineProperties(Filer: TFiler); override;
 
     function GetRecord(Buffer: PChar; GetMode: TGetMode; DoCheck: Boolean):
@@ -378,6 +375,9 @@ type
     function GetFieldData(Field: TField; Buffer: Pointer): Boolean; override;
     function GetFieldData(Field: TField; Buffer: Pointer;
       NativeFormat: Boolean): Boolean; override;
+    procedure SetFieldData(Field: TField; Buffer: Pointer;
+      NativeFormat: Boolean); override;
+    procedure SetFieldData(Field: TField; Buffer: Pointer); override;
     function CreateBlobStream(Field: TField; Mode: TBlobStreamMode): TStream;
       override;
     function UpdateStatus: TUpdateStatus; override;
diff --git a/source/childwin.pas b/source/childwin.pas
index 7378a1e0..3320bc5c 100644
--- a/source/childwin.pas
+++ b/source/childwin.pas
@@ -4603,7 +4603,7 @@ procedure TMDIChild.setNULL1Click(Sender: TObject);
 begin
   if not (DataSource1.State in [dsEdit, dsInsert]) then
     DataSource1.Edit;
-  gridData.SelectedField.Clear;
+  TZQuery(DataSource1.DataSet).SetFieldData(gridData.SelectedField, nil);
 end;
 
 
@@ -7038,4 +7038,4 @@ begin
 end;
 
 
-end.
\ No newline at end of file
+end.