Clamped Y for //expand and //contract operations.

src/com/sk89q/worldedit/Vector.java

@@ -472,6 +472,17 @@ public class Vector {
                 && getBlockZ() >= min.getBlockZ() && getBlockZ() <= max.getBlockY();
     }
 
+    /**
+     * Clamp the Y component.
+     * 
+     * @param min
+     * @param max
+     * @return
+     */
+    public Vector clampY(int min, int max) {
+        return new Vector(x, Math.max(min, Math.min(max, y)), z);
+    }
+
     /**
      * 2D transformation.
      * 

src/com/sk89q/worldedit/regions/CuboidRegion.java

@@ -168,6 +168,9 @@ public class CuboidRegion implements Region {
                 pos2 = pos2.add(new Vector(0, 0, change.getZ()));
             }
         }
+
+        pos1 = pos1.clampY(0, 127);
+        pos2 = pos2.clampY(0, 127);
     }
 
     /**
@@ -217,6 +220,9 @@ public class CuboidRegion implements Region {
                 pos2 = pos2.add(new Vector(0, 0, change.getZ()));
             }
         }
+
+        pos1 = pos1.clampY(0, 127);
+        pos2 = pos2.clampY(0, 127);
     }
 
     /**