diff --git a/src/getchar.c b/src/getchar.c
index d3d50e9..ba034bf 100644
--- a/src/getchar.c
+++ b/src/getchar.c
@@ -444,7 +444,7 @@
 	typebuf.tb_off = MAXMAPLEN;
 	typebuf.tb_len = 0;
     }
-    else		    /* remove mapped characters only */
+    else		    /* remove mapped characters at the start only */
     {
 	typebuf.tb_off += typebuf.tb_maplen;
 	typebuf.tb_len -= typebuf.tb_maplen;
diff --git a/src/misc1.c b/src/misc1.c
index 7c2d350..96d268d 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -5054,7 +5054,6 @@
     int		cx = NUL;
     int		cy = NUL;
 
-    /* TODO: multi-byte characters. */
     while (len > 0)
     {
 	cx = PTR2CHAR(px);
diff --git a/src/undo.c b/src/undo.c
index db81ba0..ba6ab37 100644
--- a/src/undo.c
+++ b/src/undo.c
@@ -216,6 +216,7 @@
 
 /*
  * Save the current line for both the "u" and "U" command.
+ * Careful: may trigger autocommands that reload the buffer.
  * Returns OK or FAIL.
  */
     int
@@ -238,8 +239,9 @@
     if (undo_off)
 	return OK;
 
-    if (top > curbuf->b_ml.ml_line_count ||
-			    top >= bot || bot > curbuf->b_ml.ml_line_count + 1)
+    if (top > curbuf->b_ml.ml_line_count
+	    || top >= bot
+	    || bot > curbuf->b_ml.ml_line_count + 1)
 	return FALSE;	/* rely on caller to do error messages */
 
     if (top + 2 == bot)
diff --git a/src/version.c b/src/version.c
index 9884bf9..f117830 100644
--- a/src/version.c
+++ b/src/version.c
@@ -729,6 +729,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    901,
+/**/
     900,
 /**/
     899,