Allow changing NavigationStateManager (#9416)

Unregister old NavigationStateManager before setting new one (backport of #9410).

Fixes #9406

1 files changed, 4 insertions, 0 deletions

diff --git a/server/src/main/java/com/vaadin/navigator/Navigator.java b/server/src/main/java/com/vaadin/navigator/Navigator.java
index 15936f6168..172ab39928 100644
--- a/server/src/main/java/com/vaadin/navigator/Navigator.java
+++ b/server/src/main/java/com/vaadin/navigator/Navigator.java
@@ -513,6 +513,10 @@ public class Navigator implements Serializable {
         if (stateManager == null) {
             stateManager = new UriFragmentManager(ui.getPage());
         }
+        if (stateManager != null && this.stateManager != null
+                && stateManager != this.stateManager) {
+            this.stateManager.setNavigator(null);
+        }
         this.stateManager = stateManager;
         this.stateManager.setNavigator(this);
         this.display = display;