diff --git a/isometric-park-fna/FNAGame.cs b/isometric-park-fna/FNAGame.cs
--- a/isometric-park-fna/FNAGame.cs
+++ b/isometric-park-fna/FNAGame.cs
@@ -624,9 +624,8 @@
     #region draw_cursor
     //drawTileAt((int)this.mouseGrid.X, (int)this.mouseGrid.Y, 2, 1, 0.85f); //between tiles and gridlines
 
-    //TODO figure out why it has to be -1
-        if (MathUtils.Between(this.mouseGrid.X, -1, this.simulation.map.MapWidth)
-                && MathUtils.Between(this.mouseGrid.Y, -1, this.simulation.map.MapHeight))
+        if (MathUtils.BetweenInclusive(this.mouseGrid.X, 0, this.simulation.map.MapWidth)
+                && MathUtils.BetweenInclusive(this.mouseGrid.Y, 0, this.simulation.map.MapHeight))
         {
             Tile.OutlineSquare(batch, this.mouseGrid.X, this.mouseGrid.Y, Color.Yellow, 1);
         }