diff --git a/salesbook.Shared/Components/Pages/Users.razor b/salesbook.Shared/Components/Pages/Users.razor
index 3feaa3a..b5a3d8f 100644
--- a/salesbook.Shared/Components/Pages/Users.razor
+++ b/salesbook.Shared/Components/Pages/Users.razor
@@ -79,7 +79,7 @@
             });
         }
 
-        FilterUsers(true);
+        FilterUsers();
     }
 
     private class UserDisplayItem
@@ -93,25 +93,32 @@
 
     private void FilterUsers(bool clearFilter)
     {
-        if (clearFilter)
+        if (clearFilter || string.IsNullOrWhiteSpace(TextToFilter))
         {
             TextToFilter = null;
             FilteredGroupedUserList = GroupedUserList;
-            StateHasChanged();
             return;
         }
 
-        if (TextToFilter == null) return;
+        var filter = TextToFilter.Trim();
+        var result = new List<UserDisplayItem>();
 
-        FilteredGroupedUserList = GroupedUserList.FindAll(x =>
-            x.User.RagSoc.Contains(TextToFilter, StringComparison.OrdinalIgnoreCase) ||
-            x.User.Indirizzo.Contains(TextToFilter, StringComparison.OrdinalIgnoreCase) ||
-            (x.User.Telefono != null && x.User.Telefono.Contains(TextToFilter, StringComparison.OrdinalIgnoreCase)) ||
-            (x.User.EMail != null && x.User.EMail.Contains(TextToFilter, StringComparison.OrdinalIgnoreCase)) ||
-            x.User.PartIva.Contains(TextToFilter, StringComparison.OrdinalIgnoreCase)
-        );
+        foreach (var item in GroupedUserList)
+        {
+            var user = item.User;
+            if (
+                (!string.IsNullOrEmpty(user.RagSoc) && user.RagSoc.Contains(filter, StringComparison.OrdinalIgnoreCase)) ||
+                (!string.IsNullOrEmpty(user.Indirizzo) && user.Indirizzo.Contains(filter, StringComparison.OrdinalIgnoreCase)) ||
+                (!string.IsNullOrEmpty(user.Telefono) && user.Telefono.Contains(filter, StringComparison.OrdinalIgnoreCase)) ||
+                (!string.IsNullOrEmpty(user.EMail) && user.EMail.Contains(filter, StringComparison.OrdinalIgnoreCase)) ||
+                (!string.IsNullOrEmpty(user.PartIva) && user.PartIva.Contains(filter, StringComparison.OrdinalIgnoreCase))
+            )
+            {
+                result.Add(item);
+            }
+        }
 
-        StateHasChanged();
+        FilteredGroupedUserList = result;
     }
 
 }
\ No newline at end of file