diff --git a/polymer/eduke32/build/src/build.c b/polymer/eduke32/build/src/build.c
index ae0928bb8..b83d660da 100644
--- a/polymer/eduke32/build/src/build.c
+++ b/polymer/eduke32/build/src/build.c
@@ -5339,7 +5339,14 @@ check_next_sector: ;
 
                     //clear out old sector's next pointers for clean deletesector
                     for (j=startwall; j<=endwall; j++)
+                    {
+#ifdef YAX_ENABLE
+                        // same thing for yax-nextwalls (only forward links!)
+                        yax_setnextwall(j, YAX_CEILING, -1);
+                        yax_setnextwall(j, YAX_FLOOR, -1);
+#endif
                         wall[j].nextwall = wall[j].nextsector = -1;
+                    }
                     deletesector(splitsect);
 
                     //Check pointers
diff --git a/polymer/eduke32/build/src/engine.c b/polymer/eduke32/build/src/engine.c
index 9f90885d4..ef83a676a 100644
--- a/polymer/eduke32/build/src/engine.c
+++ b/polymer/eduke32/build/src/engine.c
@@ -4286,11 +4286,8 @@ static void drawalls(int32_t bunch)
             {
                 if ((cz[2] <= cz[0]) && (cz[3] <= cz[1]))
                 {
-                    if (globparaceilclip
-#ifdef YAX_ENABLE
-                            || (sector[globalcursectnum].ceilingstat&4096)
-#endif
-)
+//                    if (globparaceilclip)
+                    if (getceilzofslope(sectnum, globalposx, globalposy) <= globalposz)
                         for (x=x1; x<=x2; x++)
                             if (uplc[x] > umost[x])
                                 if (umost[x] <= dmost[x])
@@ -4380,11 +4377,8 @@ static void drawalls(int32_t bunch)
             {
                 if ((fz[2] >= fz[0]) && (fz[3] >= fz[1]))
                 {
-                    if (globparaflorclip
-#ifdef YAX_ENABLE
-                            || (sector[globalcursectnum].floorstat&4096)
-#endif
-                        )
+//                    if (globparaflorclip)
+                    if (getflorzofslope(sectnum, globalposx, globalposy) >= globalposz)
                         for (x=x1; x<=x2; x++)
                             if (dplc[x] < dmost[x])
                                 if (umost[x] <= dmost[x])
@@ -7632,7 +7626,7 @@ void initspritelists(void)
 void drawrooms(int32_t daposx, int32_t daposy, int32_t daposz,
                int16_t daang, int32_t dahoriz, int16_t dacursectnum)
 {
-    int32_t i, j, cz, fz, closest;
+    int32_t i, j, /*cz, fz,*/ closest;
     int16_t *shortptr1, *shortptr2;
 
     beforedrawrooms = 0;
@@ -7751,13 +7745,13 @@ void drawrooms(int32_t daposx, int32_t daposy, int32_t daposz,
             return;
         }
     }
-
+/*
     globparaceilclip = 1;
     globparaflorclip = 1;
     getzsofslope(globalcursectnum,globalposx,globalposy,&cz,&fz);
     if (globalposz < cz) globparaceilclip = 0;
     if (globalposz > fz) globparaflorclip = 0;
-
+*/
     scansector(globalcursectnum);
 
     if (inpreparemirror)
diff --git a/polymer/eduke32/source/astub.c b/polymer/eduke32/source/astub.c
index 29d32f551..74392b16c 100644
--- a/polymer/eduke32/source/astub.c
+++ b/polymer/eduke32/source/astub.c
@@ -6068,14 +6068,27 @@ static void Keys3d(void)
         //        printext256(1*4,1*8,11,-1,tempbuf,0);
     }
 
-    if (keystatus[KEYSC_QUOTE] && PRESSED_KEYSC(I))  // ' i
+    if (keystatus[KEYSC_I])
     {
-        showinvisibility = !showinvisibility;
+        keystatus[KEYSC_I] = 0;
+
+        if (keystatus[KEYSC_QUOTE])
+        {
+            if (AIMING_AT_SPRITE)
+            {
+                sprite[searchwall].cstat ^= 32768;
+                message("Sprite %d made %svisible", searchwall, (sprite[searchwall].cstat&32768) ? "in":"");
+            }
+        }
+        else  // ' i
+        {
+            showinvisibility = !showinvisibility;
 #ifndef YAX_ENABLE
-        message("Show invisible sprites %s", showinvisibility?"enabled":"disabled");
+            message("Show invisible sprites %s", showinvisibility?"enabled":"disabled");
 #else
-        message("Show invisible objects %s", showinvisibility?"enabled":"disabled");
+            message("Show invisible objects %s", showinvisibility?"enabled":"disabled");
 #endif
+        }
     }
 
     if (keystatus[KEYSC_QUOTE] && PRESSED_KEYSC(X)) // ' x