// Restores a previously deleted material
        public void restoreMaterial(int materialId)
        {
            // Delete form Db
            MaterialModel.restoreMaterial(materialId);

            // Remove from deleted list and add to active list
            MaterialModel restoredMaterial = deletedMaterialList.Where(mat => mat.materialId == materialId).First();

            deletedMaterialList.Remove(restoredMaterial);

            materialList.Add(restoredMaterial);
            originalMaterialList.Add(restoredMaterial);

            // Refilter the materials
            filterMaterials();
        }