--- a/WebBrowser/Session/SessionManager.py	Tue Jul 04 19:44:30 2017 +0200
+++ b/WebBrowser/Session/SessionManager.py	Wed Jul 05 19:38:06 2017 +0200
@@ -204,7 +204,7 @@
             
             if window is activeWindow:
                 sessionData["CurrentWindowIndex"] = \
-                    len(sessionData["Windows"]) -1
+                    len(sessionData["Windows"]) - 1
         
         if sessionData["Windows"]:
             sessionFile = open(sessionFileName, "w")