diff --git a/mailnews/compose/public/nsIComposer.h b/mailnews/compose/public/nsIComposer.h
index cbc2b3575419..f3d6ee0bdf39 100644
--- a/mailnews/compose/public/nsIComposer.h
+++ b/mailnews/compose/public/nsIComposer.h
@@ -17,8 +17,8 @@
 /* {82041532-D73E-11d2-82A9-00805F2A0107} */
 #define NS_ICOMPOSER_IID_STR "82041532-D73E-11d2-82A9-00805F2A0107"
 #define NS_ICOMPOSER_IID \
-  {0x82041532, 0xd73e, 0x11d2, \
-    { 0x82, 0xa9, 0x0, 0x80, 0x5f, 0x2a, 0x1, 0x7 }}
+  {0x82041532, 0xD73E, 0x11d2, \
+    { 0x82, 0xA9, 0x00, 0x80, 0x5F, 0x2A, 0x01, 0x07 }}
 
 class nsIComposer : public nsISupports {
  public: