From 3c1e9fb02c8fc376c16f9069a58f17227f7f58de Mon Sep 17 00:00:00 2001
From: =?utf8?q?Leif=20=C3=85strand?= <leif@vaadin.com>
Date: Fri, 10 Aug 2012 11:30:24 +0300
Subject: [PATCH] Allow detaching Extension once (#9282)

---
 .../extensions/AbstractExtensionConnector.java      | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/com/vaadin/terminal/gwt/client/extensions/AbstractExtensionConnector.java b/src/com/vaadin/terminal/gwt/client/extensions/AbstractExtensionConnector.java
index bcefcf05cb..408f03f6cb 100644
--- a/src/com/vaadin/terminal/gwt/client/extensions/AbstractExtensionConnector.java
+++ b/src/com/vaadin/terminal/gwt/client/extensions/AbstractExtensionConnector.java
@@ -8,17 +8,26 @@ import com.vaadin.terminal.gwt.client.ServerConnector;
 import com.vaadin.terminal.gwt.client.ui.AbstractConnector;
 
 public abstract class AbstractExtensionConnector extends AbstractConnector {
+    boolean hasBeenAttached = false;
+
     @Override
     public void setParent(ServerConnector parent) {
         ServerConnector oldParent = getParent();
-        if (oldParent != null && oldParent != parent) {
+        if (oldParent == parent) {
+            // Nothing to do
+            return;
+        }
+        if (hasBeenAttached && parent != null) {
             throw new IllegalStateException(
                     "An extension can not be moved from one parent to another.");
         }
 
         super.setParent(parent);
 
-        extend(parent);
+        if (parent != null) {
+            extend(parent);
+            hasBeenAttached = true;
+        }
     }
 
     protected void extend(ServerConnector target) {
-- 
2.39.5