Index: draw.html
==================================================================
--- draw.html
+++ draw.html
@@ -92,17 +92,10 @@
 
 var view_transform =
     [[1, 0, 0],
      [0, 1, 0],
      [0, 0, 1]];
-    
-
-
-
-
-
-
 
             
 
 var key_state = {};
 var key_state_augmentation_timeout = 150; // the permissible time in milliseconds since the last key event to still allow the key state to augment instead of clearing.
@@ -339,11 +332,11 @@
 					   alreadySelected = true; 
 					   break; }}}
 			else{
 				selected_points.length = 0;}
 				
-			if(!alreadySelected) selected_points.push(highlight_object); }
+			if(!alreadySelected && highlight_object < points.length) selected_points.push(highlight_object); }
 
 		else if(!key_state[16] || !key_state[16].state)
 			selected_points.length = 0; }
 		
 		

Index: matrix_vector_lib.js
==================================================================
--- matrix_vector_lib.js
+++ matrix_vector_lib.js
@@ -258,11 +258,11 @@
 // http://inside.mines.edu/~gmurray/ArbitraryAxisRotation/ArbitraryAxisRotation.html
 // creates a rotation matrix about the given vector.
 //
 function vector_rotation(vector, s){
 	if(!vector) throw "vector argument to vector_rotation missing";
-	if(!s) throw "angle argument to vector_rotation missing";
+	if(s === null || s === undefined) throw "angle argument to vector_rotation missing";
 	
     var len = Math.sqrt(vector[0]*vector[0]
                         + vector[1]*vector[1]
                         + vector[2]*vector[2]);