diff --git a/etg/_core.py b/etg/_core.py
index 6192fdf7..874962ef 100644
--- a/etg/_core.py
+++ b/etg/_core.py
@@ -419,6 +419,11 @@ def run():
             ])
 
 
+    module.addCppFunction('bool', 'IsMainThread', '()',
+        doc="Returns True if the current thread is what wx considers the GUI thread.",
+        body="return wxThread::IsMain();")
+    
+
     module.addInitializerCode("""\
         wxPyPreInit(sipModuleDict);
         """)
diff --git a/etg/app.py b/etg/app.py
index 1fd70007..df723b8f 100644
--- a/etg/app.py
+++ b/etg/app.py
@@ -270,12 +270,12 @@ def run():
                     """,
                 body="""\
                     if self.frame is None:
-                        if not wx.Thread.IsMain():
+                        if not wx.IsMainThread():
                             wx.CallAfter(self.CreateOutputWindow, text)
                         else:
                             self.CreateOutputWindow(text)
                     else:
-                        if not wx.Thread.IsMain():
+                        if not wx.IsMainThread():
                             wx.CallAfter(self.text.AppendText, text)
                         else:
                             self.text.AppendText(text)