diff --git a/content/messages.js.php b/content/messages.js.php
index 5e4e606f0..2f21bc125 100644
--- a/content/messages.js.php
+++ b/content/messages.js.php
@@ -124,6 +124,18 @@ function MessageAuswahl()
 	else
 	{
 		var text = getTreeCellText(tree, 'messages-tree-body', tree.currentIndex);
+		var recipient_id = getTreeCellText(tree, 'messages-tree-recipient_id', tree.currentIndex);
+		// Antworten ist nur moeglich wenn die Message vom User kommt
+		if(recipient_id==MessagePersonID)
+		{
+			document.getElementById('messages-tree-popup-answer').disabled=true;
+			document.getElementById('messages-button-answer').disabled=true;
+		}
+		else
+		{
+			document.getElementById('messages-tree-popup-answer').disabled=false;
+			document.getElementById('messages-button-answer').disabled=false;
+		}
 	}
 	document.getElementById('message-wysiwyg').value=text;
 }
diff --git a/content/messages.xul.php b/content/messages.xul.php
index 86cccb3ae..dd7340b59 100644
--- a/content/messages.xul.php
+++ b/content/messages.xul.php
@@ -69,8 +69,8 @@ echo ']>
 	</menupopup>
 </popupset>
 <hbox style="padding-top: 10px">
-	<button oncommand="MessagesNewMessage()" label="Neue Nachricht schicken"/>
-	<button oncommand="MessagesSendAnswer()" label="Antworten"/>
+	<button oncommand="MessagesNewMessage()" id="messages-button-new" label="Neue Nachricht schicken"/>
+	<button oncommand="MessagesSendAnswer()" id="messages-button-answer" label="Antworten"/>
 </hbox>
 
 <hbox>