Update 07-managing-relationships.md

docs/03-resources/07-managing-relationships.md

@@ -1023,6 +1023,22 @@ public function table(Table $table): Table
 }
 ```
 
+<Aside variant="danger">
+    `modifyQueryUsing()` scopes the query for records that already belong to the relationship — the table listing, and actions that operate on its rows, such as `DetachAction`, `DissociateAction`, and bulk actions. It is **not** applied to the records available to `AttachAction` or `AssociateAction`, since those records are outside the relationship by definition.
+
+    To restrict which records may be attached or associated, scope the options using the `recordSelectOptionsQuery()` method on the action. Filament resolves the submitted record against that query, so records outside it are rejected, even if a user tampers with the submitted modal state:
+
+    ```php
+    use Filament\Actions\AttachAction;
+    use Illuminate\Database\Eloquent\Builder;
+
+    AttachAction::make()
+        ->recordSelectOptionsQuery(fn (Builder $query) => $query->where('is_active', true))
+    ```
+
+    Learn more about scoping the options to [attach](#scoping-the-options-to-attach) or [associate](#scoping-the-options-to-associate).
+</Aside>
+
 ## Customizing the relation manager title
 
 To set the title of the relation manager, you can use the `$title` property on the relation manager class: