--- a/Plugins/VcsPlugins/vcsMercurial/HgDialog.py	Wed Mar 22 18:45:15 2017 +0100
+++ b/Plugins/VcsPlugins/vcsMercurial/HgDialog.py	Wed Mar 22 18:50:20 2017 +0100
@@ -118,7 +118,7 @@
         self.__finish()
     
     def startProcess(self, args, workingDir=None, showArgs=True,
-                     environment={}):
+                     environment=None):
         """
         Public slot used to start the process.