diff --git a/PySimpleGUIWeb/PySimpleGUIWeb.py b/PySimpleGUIWeb/PySimpleGUIWeb.py
index 42521a24..5bdc3463 100644
--- a/PySimpleGUIWeb/PySimpleGUIWeb.py
+++ b/PySimpleGUIWeb/PySimpleGUIWeb.py
@@ -2590,7 +2590,7 @@ class Window:
                  alpha_channel=1, return_keyboard_events=False, use_default_focus=True, text_justification=None,
                  no_titlebar=False, grab_anywhere=False, keep_on_top=False, resizable=True, disable_close=False,
                  disable_minimize=False, background_image=None,
-                 web_debug=False, web_ip='0.0.0.0', web_port=0, web_start_browser=True, web_update_interval=.00001, web_multiple_instance=True ):
+                 web_debug=False, web_ip='0.0.0.0', web_port=0, web_start_browser=True, web_update_interval=.00001, web_multiple_instance=False ):
         '''
 
         :param title:
diff --git a/PySimpleGUIWeb/readme.md b/PySimpleGUIWeb/readme.md
index 4fac9b96..2e012d57 100644
--- a/PySimpleGUIWeb/readme.md
+++ b/PySimpleGUIWeb/readme.md
@@ -236,8 +236,9 @@ New features
    * The default value is TRUE (Previously I think default was False by Remi)
    * Was made as a result of comment on repl.it.
 
+## 0.15.0 PySimpleGUIWeb 5-Mar-2019
 
-
+* Made the multiple_instance parameter FALSE by default (was messing up badly with True)
 
 # Design        
 # Author