Index: src/proto.h
===================================================================
--- src/proto.h	(revision 4977)
+++ src/proto.h	(working copy)
@@ -249,6 +249,7 @@
 
 /* All functions in cut.c. */
 void cutbuffer_reset(void);
+bool keeping_cutbuffer(void);
 void cut_line(void);
 #ifndef NANO_TINY
 void cut_marked(void);
Index: src/text.c
===================================================================
--- src/text.c	(revision 4977)
+++ src/text.c	(working copy)
@@ -854,7 +854,7 @@
      * on the same lineno, we need to abort here. */
     u = fs->current_undo;
     if (u && u->mark_begin_lineno == fs->current->lineno &&
-	((current_action == CUT && u->type == CUT && !u->mark_set) ||
+	((current_action == CUT && u->type == CUT && !u->mark_set && keeping_cutbuffer()) ||
 	(current_action == ADD && u->type == ADD && u->mark_begin_x == fs->current_x)))
 	return;
 
Index: src/cut.c
===================================================================
--- src/cut.c	(revision 4977)
+++ src/cut.c	(working copy)
@@ -37,6 +37,12 @@
     keep_cutbuffer = FALSE;
 }
 
+/* Returns the status of cutbuffer preservation. */
+inline bool keeping_cutbuffer(void)
+{
+    return keep_cutbuffer;
+}
+
 /* If we aren't on the last line of the file, move all the text of the
  * current line, plus the newline at the end, into the cutbuffer.  If we
  * are, move all of the text of the current line into the cutbuffer.  In
@@ -172,10 +178,11 @@
 	 * file into the cutbuffer. */
 	cut_to_eof();
     } else if (openfile->mark_set) {
-	/* If the mark is on, move the marked text to the cutbuffer, and
-	 * turn the mark off. */
+	/* If the mark is on, move the marked text to the cutbuffer, turn
+	 * the mark off, and blow away the cutbuffer on the next cut. */
 	cut_marked();
 	openfile->mark_set = FALSE;
+	cutbuffer_reset();
     } else if (ISSET(CUT_TO_END))
 	/* If the CUT_TO_END flag is set, move all text up to the end of
 	 * the line into the cutbuffer. */
@@ -245,10 +252,20 @@
 
 #ifndef NANO_TINY
 /* Move text from the current filestruct into the cutbuffer, and copy it
- * back into the filestruct afterward. */
+ * back into the filestruct afterward.  If the mark is set or the cursor
+ * was moved, blow away previous contents of the cutbuffer. */
 void do_copy_text(void)
 {
+    static struct filestruct *next_contiguous_line = NULL;
+    bool mark_set = openfile->mark_set;
+
+    if (mark_set || openfile->current != next_contiguous_line)
+	cutbuffer_reset();
+
     do_cut_text(TRUE, FALSE, FALSE);
+
+    /* If the mark was set, blow away the cutbuffer on the next copy. */
+    next_contiguous_line = (mark_set ? NULL : openfile->current);
 }
 
 /* Cut from the current cursor position to the end of the file. */