Hide form field

Dear all,

I want to hide form field by placing other control on it.

Plz check my code:

oForm = SBO_Application.Forms.GetFormByTypeAndCount(pVal.FormType, pVal.FormTypeCount);

SAPbouiCOM.Item oItem = oForm.Items.Item("30");

SAPbouiCOM.Item oNewItem = null;

oNewItem = oForm.Items.Add("cmb_SE", SAPbouiCOM.BoFormItemTypes.it_COMBO_BOX);

oNewItem.Left = oItem.Left;

oNewItem.Top = oItem.Top;

oNewItem.Width = 3 * oItem.Width;

oCombo = (SAPbouiCOM.ComboBox)oForm.Items.Item("cmb_SE").Specific;

oItem = oForm.Items.Item("cmb_SE");

oItem.Visible = false;

But the new created control is not overlaping existing control.

I have also use the same top of existing field