diff --git a/src/winio.c b/src/winio.c
index ead5b018..67ea2432 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -369,22 +369,19 @@ int convert_sequence(const int *seq, size_t length, int *consumed)
 						}
 						break;
 					case '2':  /* Shift */
-					case '4':  /* Shift+Alt */
-					case '6':  /* Shift+Ctrl */
-						if (length > 2) {
-							*consumed = 3;
-							/* Allow typing digits on the numeric keypad without
-							 * engaging NumLock.  Esc O 2 p == Shift-0, .... */
-							return (seq[2] - 0x40);
-						}
-						break;
 					case '3':  /* Alt */
+					case '4':  /* Shift+Alt */
 					case '5':  /* Ctrl */
+					case '6':  /* Shift+Ctrl */
 					case '7':  /* Alt+Ctrl */
+					case '8':  /* Shift+Alt+Ctrl */
 						if (length > 2) {
 							*consumed = 3;
-							switch (seq[2]) {
+							/* Do not accept multiple modifiers. */
+							if (seq[1] == '4' || seq[1] > '5')
+								return FOREIGN_SEQUENCE;
 #ifndef NANO_TINY
+							switch (seq[2]) {
 								case 'A': /* Esc O 5 A == Ctrl-Up on Haiku. */
 									return CONTROL_UP;
 								case 'B': /* Esc O 5 B == Ctrl-Down on Haiku. */
@@ -393,18 +390,12 @@ int convert_sequence(const int *seq, size_t length, int *consumed)
 									return CONTROL_RIGHT;
 								case 'D': /* Esc O 5 D == Ctrl-Left on Haiku. */
 									return CONTROL_LEFT;
-#endif
-								case 'M': /* Esc O . M == modified Enter on keypad. */
-									return KEY_ENTER;
-								case 'j': /* Esc O . j == modified '*' on keypad. */
-									return '*';
-								case 'k': /* Esc O . k == modified '+' on keypad. */
-									return '+';
-								case 'm': /* Esc O . m == modified '-' on keypad. */
-									return '-';
-								case 'o': /* Esc O . o == modified '/' on keypad. */
-									return '/';
 							}
+#endif
+							/* Translate Shift+digit on the keypad to the digit
+							 * (Esc O 2 p == Shift-0, ...), modifier+operator to
+							 * the operator, and modifier+Enter to CR. */
+							return (seq[2] - 0x40);
 						}
 						break;
 					case 'A': /* Esc O A == Up on VT100/VT320. */