--- a/Plugins/VcsPlugins/vcsMercurial/HgDiffDialog.py	Sat Jun 16 18:28:31 2012 +0200
+++ b/Plugins/VcsPlugins/vcsMercurial/HgDiffDialog.py	Sun Jun 17 13:34:46 2012 +0200
@@ -118,6 +118,9 @@
             self.vcs.addArguments(args, self.vcs.options['global'])
             self.vcs.addArguments(args, self.vcs.options['diff'])
             
+            if self.vcs.hasSubrepositories():
+                args.append("--subrepos")
+            
             if bundle:
                 args.append('--repository')
                 args.append(bundle)