diff --git a/SanSystem/frmStrassenList.cs b/SanSystem/frmStrassenList.cs
index 18f4ceb..ba97d5d 100644
--- a/SanSystem/frmStrassenList.cs
+++ b/SanSystem/frmStrassenList.cs
@@ -166,7 +166,7 @@ namespace SanSystem
         {
             if ((sender as TreeView).SelectedNode == null) return;
             string selectedStreetName = (string)(sender as TreeView).SelectedNode.Tag;
-            if (selectedStreetName.Equals("")) return;
+            if (selectedStreetName == null || selectedStreetName.Equals("")) return;
             aktuallStreetName = selectedStreetName;
             frmObjekteList frmObjekteList = new frmObjekteList(selectedStreetName);
             frmObjekteList.MdiParent = this.MdiParent;