--- gimp-1.3-orig/app/core/gimpimage-projection.c	2003-09-16 22:43:35.000000000 +0200
+++ gimp-1.3-mine/app/core/gimpimage-projection.c	2003-11-30 13:19:17.000000000 +0100
@@ -246,7 +246,8 @@ gimp_image_invalidate (GimpImage *gimage
           {
             tile_invalidate_tile (&tile, tm, j, i);
             if (j < x1)
-              startx = MAX (startx, (j + tile_ewidth(tile)));
+              startx = MAX (startx,
+                            (j - (j % TILE_WIDTH) + tile_ewidth(tile)));
             else
               endx = MIN (endx, j);
           }
@@ -254,7 +255,8 @@ gimp_image_invalidate (GimpImage *gimage
           {
             tile_invalidate_tile (&tile, tm, j, i);
             if (i < y1)
-              starty = MAX (starty, (i + tile_eheight(tile)));
+              starty = MAX (starty,
+                            (i - (i % TILE_HEIGHT) + tile_eheight(tile)));
             else
               endy = MIN (endy, i);
           }
