diff --git a/src/cmdlib.h b/src/cmdlib.h
index 05e515374..b035842cd 100644
--- a/src/cmdlib.h
+++ b/src/cmdlib.h
@@ -16,7 +16,7 @@
 #include <stdarg.h>
 
 // the dec offsetof macro doesnt work very well...
-#define myoffsetof(type,identifier) ((size_t)&((type *)1)->identifier - 1)
+#define myoffsetof(type,identifier) ((size_t)&((type *)alignof(type))->identifier - alignof(type))
 
 int		Q_filelength (FILE *f);
 bool FileExists (const char *filename);
diff --git a/src/p_pspr.cpp b/src/p_pspr.cpp
index ebfc14da3..e63490110 100644
--- a/src/p_pspr.cpp
+++ b/src/p_pspr.cpp
@@ -1169,8 +1169,17 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_ClearOverlays)
 
 	int count = 0;
 	DPSprite *pspr = player->psprites;
+	int startID = (pspr != nullptr) ? pspr->GetID() : start;
+	bool first = true;
 	while (pspr != nullptr)
 	{
+		if (pspr->GetID() == startID)
+		{
+			if (first)
+				first = false;
+			else
+				break;
+		}
 		int id = pspr->GetID();
 
 		//Do not wipe out layer 0. Ever.
diff --git a/src/portal.cpp b/src/portal.cpp
index f180a4fbf..bf919f09a 100644
--- a/src/portal.cpp
+++ b/src/portal.cpp
@@ -288,7 +288,7 @@ static void SetRotation(FLinePortal *port)
 			}
 			else
 			{
-				port->mFlags &= PORTF_POLYOBJ;
+				port->mFlags &= ~PORTF_POLYOBJ;
 			}
 		}
 		else
diff --git a/wadsrc/static/language.eng b/wadsrc/static/language.eng
index bf0a0a91d..365005fb9 100644
--- a/wadsrc/static/language.eng
+++ b/wadsrc/static/language.eng
@@ -108,5 +108,7 @@ CMPTMNU_SECTORSOUNDS = "Sector sounds use centre as source";
 OPTVAL_MAPDEFINEDCOLORSONLY = "Map defined colours only";
 C_GRAY = "\ccgrey";
 C_DARKGRAY = "\cudark grey";
+DSPLYMNU_MOVEBOB = "View bob amount while moving";
+DSPLYMNU_STILLBOB = "View bob amount while not moving";
 
 OPTVAL_ANYFIXEDCOLORMAP    = "Any fixed colourmap";
diff --git a/wadsrc/static/menudef.txt b/wadsrc/static/menudef.txt
index 0820b4d69..36717c7e4 100644
--- a/wadsrc/static/menudef.txt
+++ b/wadsrc/static/menudef.txt
@@ -700,6 +700,8 @@ OptionMenu "VideoOptions"
 	Option "$DSPLYMNU_NOMONSTERINTERPOLATION",	"nomonsterinterpolation", "NoYes"
 	Slider "$DSPLYMNU_MENUDIM",					"dimamount", 0, 1.0, 0.05, 2
 	ColorPicker "$DSPLYMNU_DIMCOLOR",			"dimcolor"
+	Slider "$DSPLYMNU_MOVEBOB",			"movebob", 0, 1.0, 0.05, 2
+	Slider "$DSPLYMNU_STILLBOB",		"stillbob", 0, 1.0, 0.05, 2
 }
 
 //-------------------------------------------------------------------------------------------