diff --git a/docs/rh-log.txt b/docs/rh-log.txt
index 485ff6ab0..da3473894 100644
--- a/docs/rh-log.txt
+++ b/docs/rh-log.txt
@@ -1,4 +1,5 @@
 January 24, 2009  (Changes by Graf Zahl)
+- Fixed: The sight checking code didn't initialize the myseethrough variable.
 - Fixed: With COMPAT_TRACE switched on linedef actions on lines having
   the same sector on both sides were not triggered.
 
diff --git a/src/p_sight.cpp b/src/p_sight.cpp
index 19a5e68ef..2e0282213 100644
--- a/src/p_sight.cpp
+++ b/src/p_sight.cpp
@@ -76,6 +76,7 @@ public:
 
 		SeePastBlockEverything = flags & 6;
 		SeePastShootableLines = flags & 4;
+		myseethrough = FF_SEETHROUGH;
 	}
 };