diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index fc665a50c..4130b3148 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,4 +1,7 @@
 September 17, 2009  (Changes by Graf Zahl)
+- Fixed: Unmorphing while invulnerable was blocked.
+- Various cleanup changes.
+- fixed Dog's class name in DEHSUPP.
 - Renamed plane flags from SECF_* to PLANEF_*.
 - Changed Heretic's plat raise type to use a flag to block further sector movement
   instead of keeping the dead thinker around to block the sector.
diff --git a/src/g_shared/a_morph.cpp b/src/g_shared/a_morph.cpp
index f319f5414..9ebec54ca 100644
--- a/src/g_shared/a_morph.cpp
+++ b/src/g_shared/a_morph.cpp
@@ -192,10 +192,11 @@ bool P_UndoPlayerMorph (player_t *activator, player_t *player, bool force)
 		return false;
 	}
 
-	if ((pmo->flags2 & MF2_INVULNERABLE) && ((player != activator) || (!(player->MorphStyle & MORPH_WHENINVULNERABLE))))
-	{ // Immune when invulnerable unless this is something we initiated.
-		// If the WORLD is the initiator, the same player should be given
-		// as the activator; WORLD initiated actions should always succeed.
+	if ((pmo->flags2 & MF2_INVULNERABLE) // If the player is invulnerable
+		&& ((player != activator)		// and either did not decide to unmorph,
+		|| (!((player->MorphStyle & MORPH_WHENINVULNERABLE)  // or the morph style does not allow it
+		&& (player->MorphStyle != MORPH_OLDEFFECTS))))) // (but standard morph styles always allow it),
+	{ // Then the player is immune to the unmorph.
 		return false;
 	}