diff --git a/src/g_doom/a_possessed.cpp b/src/g_doom/a_possessed.cpp
index e435bff14..c792a489d 100644
--- a/src/g_doom/a_possessed.cpp
+++ b/src/g_doom/a_possessed.cpp
@@ -112,7 +112,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_CPosRefire)
 	if (!self->target
 		|| P_HitFriend (self)
 		|| self->target->health <= 0
-		|| !P_CheckSight (self, self->target, 0) )
+		|| !P_CheckSight (self, self->target, SF_SEEPASTBLOCKEVERYTHING|SF_SEEPASTSHOOTABLELINES))
 	{
 		self->SetState (self->SeeState);
 	}
diff --git a/src/g_doom/a_spidermaster.cpp b/src/g_doom/a_spidermaster.cpp
index a29561b56..1e3628c69 100644
--- a/src/g_doom/a_spidermaster.cpp
+++ b/src/g_doom/a_spidermaster.cpp
@@ -22,7 +22,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SpidRefire)
 	if (!self->target
 		|| P_HitFriend (self)
 		|| self->target->health <= 0
-		|| !P_CheckSight (self, self->target, 0) )
+		|| !P_CheckSight (self, self->target, SF_SEEPASTBLOCKEVERYTHING|SF_SEEPASTSHOOTABLELINES))
 	{
 		self->SetState (self->SeeState);
 	}
diff --git a/src/g_strife/a_sentinel.cpp b/src/g_strife/a_sentinel.cpp
index 5f012cfb1..9f582dcd5 100644
--- a/src/g_strife/a_sentinel.cpp
+++ b/src/g_strife/a_sentinel.cpp
@@ -79,7 +79,7 @@ DEFINE_ACTION_FUNCTION(AActor, A_SentinelRefire)
 	{
 		if (self->target == NULL ||
 			self->target->health <= 0 ||
-			!P_CheckSight (self, self->target) ||
+			!P_CheckSight (self, self->target, SF_SEEPASTBLOCKEVERYTHING|SF_SEEPASTSHOOTABLELINES) ||
 			P_HitFriend(self) ||
 			pr_sentinelrefire() < 40)
 		{
diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index 095540caa..45038d83f 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -2847,7 +2847,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_MonsterRefire)
 	if (!self->target
 		|| P_HitFriend (self)
 		|| self->target->health <= 0
-		|| !P_CheckSight (self, self->target, 0) )
+		|| !P_CheckSight (self, self->target, SF_SEEPASTBLOCKEVERYTHING|SF_SEEPASTSHOOTABLELINES) )
 	{
 		ACTION_JUMP(jump);
 	}