--- a/contrib/mergetools.hgrc	Thu May 29 15:41:16 2014 -0700
+++ b/contrib/mergetools.hgrc	Thu May 29 12:25:25 2014 -0700
@@ -71,6 +71,12 @@
 ecmerge.gui=True
 ecmerge.diffargs=$parent $child --mode=diff2 --title1='$plabel1' --title2='$clabel'
 
+# editmerge is a small script shipped in contrib.
+# It needs this config otherwise it behaves the same as internal:local
+editmerge.args=$output
+editmerge.check=changed
+editmerge.premerge=keep
+
 filemerge.executable=/Developer/Applications/Utilities/FileMerge.app/Contents/MacOS/FileMerge
 filemerge.args=-left $other -right $local -ancestor $base -merge $output
 filemerge.gui=True