diff --git a/src/viewport.cpp b/src/viewport.cpp
--- a/src/viewport.cpp
+++ b/src/viewport.cpp
@@ -821,7 +821,7 @@ static void AddStringToDraw(int x, int y
  */
 static void DrawSelectionSprite(SpriteID image, PaletteID pal, const TileInfo *ti, int z_offset, FoundationPart foundation_part)
 {
-	/* FIXME: This is not totally valid for some autorail highlights, that extent over the edges of the tile. */
+	/* FIXME: This is not totally valid for some autorail highlights that extend over the edges of the tile. */
 	if (_vd.foundation[foundation_part] == -1) {
 		/* draw on real ground */
 		AddTileSpriteToDraw(image, pal, ti->x, ti->y, ti->z + z_offset);