diff --git a/docs/03-resources/07-managing-relationships.md b/docs/03-resources/07-managing-relationships.md
index b929e326fd..53be1e46e5 100644
--- a/docs/03-resources/07-managing-relationships.md
+++ b/docs/03-resources/07-managing-relationships.md
@@ -114,6 +114,19 @@ public static function getRelations(): array
 
 Once a table and form have been defined for the relation manager, visit the [Edit](editing-records) or [View](viewing-records) page of your resource to see it in action.
 
+### Customizing the relation manager's URL parameter
+
+If you pass a key to the array returned from `getRelations()`, it will be used in the URL for that relation manager when switching been multiple relation managers. For example, you can pass `posts` to use `?relation=posts` in the URL instead of a numeric array index:
+
+```php
+public static function getRelations(): array
+{
+    return [
+        'posts' => RelationManagers\PostsRelationManager::class,
+    ];
+}
+```
+
 ### Read-only mode
 
 Relation managers are usually displayed on either the Edit or View page of a resource. On the View page, Filament will automatically hide all actions that modify the relationship, such as create, edit, and delete. We call this "read-only mode", and it is there by default to preserve the read-only behavior of the View page. However, you can disable this behavior, by overriding the `isReadOnly()` method on the relation manager class to return `false` all the time:
diff --git a/docs/03-resources/08-nesting.md b/docs/03-resources/08-nesting.md
index 589e74c5a6..400b9609ab 100644
--- a/docs/03-resources/08-nesting.md
+++ b/docs/03-resources/08-nesting.md
@@ -65,3 +65,18 @@ public static function getParentResourceRegistration(): ?ParentResourceRegistrat
 ```
 
 You can omit the calls to `relationship()` and `inverseRelationship()` if you want to use the default names.
+
+## Registering a relation manager with the correct URL
+
+When dealing with a nested resource that is listed by a relation manager, and the relation manager is amongst others on that page, you may notice that the URL to it is not correct when you redirect from the nested resource back to it. This is because each relation manager registered on a resource is assigned an integer, which is used to identify it in the URL when switching between multiple relation managers. For example, `?relation=0` might represent one relation manager in the URL, and `?relation=1` might represent another.
+
+When redirecting from a nested resource back to a relation manager, Filament will assume that the relationship name is used to identify that relation manager in the URL. For example, if you have a nested `LessonResource` and a `LessonsRelationManager`, the relationship name is `lessons`, and should be used as the [URL parameter key](managing-relationships#customizing-the-relation-managers-url-parameter) for that relation manager when it is registered:
+
+```php
+public static function getRelations(): array
+{
+    return [
+        'lessons' => LessonsRelationManager::class,
+    ];
+}
+```
diff --git a/docs/14-upgrade-guide.md b/docs/14-upgrade-guide.md
index e69c64adff..2a91541b0e 100644
--- a/docs/14-upgrade-guide.md
+++ b/docs/14-upgrade-guide.md
@@ -392,8 +392,8 @@ The following code examples illustrate how field state may now return an enum in
 ```php
 use App\Enums\Status;
 use Filament\Forms\Components\Select;
-use Filament\Forms\Components\TextInput
-;use Filament\Schemas\Components\Utilities\Get;
+use Filament\Forms\Components\TextInput;
+use Filament\Schemas\Components\Utilities\Get;
 
 Select::make('status')
     ->options(Status::class)
@@ -411,6 +411,16 @@ $data = $this->form->getState();
 ```
 </Disclosure>
 
+<Disclosure x-show="packages.includes('panels')">
+<span slot="summary">URL parameter names have changed</span>
+
+Filament v4 has renamed some of the URL parameters that are used on resource pages, to make them cleaner in the URL and easier to remember:
+
+- `activeRelationManager` has been renamed to just `relation` on Edit / View resource pages.
+
+To find out if you are using this parameter in your code, try searching for `'activeRelationManager' => ` (etc.) in your code, and looking for areas where you are using `::getUrl()` or another method of generating a URL with a parameter.
+</Disclosure>
+
 <Disclosure x-show="packages.includes('panels')">
 <span slot="summary">Automatic tenancy global scoping and association</span>
 
diff --git a/packages/panels/src/Resources/Resource/Concerns/CanGenerateUrls.php b/packages/panels/src/Resources/Resource/Concerns/CanGenerateUrls.php
index 7661f7352f..55cb265096 100644
--- a/packages/panels/src/Resources/Resource/Concerns/CanGenerateUrls.php
+++ b/packages/panels/src/Resources/Resource/Concerns/CanGenerateUrls.php
@@ -81,7 +81,7 @@ trait CanGenerateUrls
 
             if ($parentResource::hasPage('view')) {
                 return $parentResource::getUrl('view', [
-                    'activeRelationManager' => $parentResourceRegistration->getRelationshipName(),
+                    'relation' => $parentResourceRegistration->getRelationshipName(),
                     ...$parameters,
                     'record' => $record,
                 ], $isAbsolute, $panel, $tenant, $shouldGuessMissingParameters);
@@ -89,7 +89,7 @@ trait CanGenerateUrls
 
             if ($parentResource::hasPage('edit')) {
                 return $parentResource::getUrl('edit', [
-                    'activeRelationManager' => $parentResourceRegistration->getRelationshipName(),
+                    'relation' => $parentResourceRegistration->getRelationshipName(),
                     ...$parameters,
                     'record' => $record,
                 ], $isAbsolute, $panel, $tenant, $shouldGuessMissingParameters);