diff --git a/tmux.1 b/tmux.1
index 9b565dd1..94e60758 100644
--- a/tmux.1
+++ b/tmux.1
@@ -2078,10 +2078,8 @@ Key bindings default to emacs.
 .Op Ic on | off
 .Xc
 Mouse state in modes.
-If on,
-.Nm
-will respond to mouse clicks by moving the cursor in copy mode or selecting an
-option in choice mode.
+If on, the mouse may be used to copy a selection by dragging in copy mode, or
+to select an option in choice mode.
 .Pp
 .It Xo Ic monitor-activity
 .Op Ic on | off
diff --git a/tmux.h b/tmux.h
index 961019d8..3069f89b 100644
--- a/tmux.h
+++ b/tmux.h
@@ -541,7 +541,8 @@ struct mode_key_table {
 #define MODE_KCURSOR 0x4
 #define MODE_KKEYPAD 0x8	/* set = application, clear = number */
 #define MODE_MOUSE 0x10
-#define MODE_WRAP 0x20		/* whether lines wrap */
+#define MODE_MOUSEMOTION 0x20
+#define MODE_WRAP 0x40		/* whether lines wrap */
 
 /*
  * A single UTF-8 character.
@@ -1086,7 +1087,7 @@ struct client {
 
 #define CLIENT_TERMINAL 0x1
 #define CLIENT_PREFIX 0x2
-#define CLIENT_MOUSE 0x4
+/* 0x4 unused */
 #define CLIENT_REDRAW 0x8
 #define CLIENT_STATUS 0x10
 #define CLIENT_REPEAT 0x20	/* allow command to repeat within repeat time */
diff --git a/tty-keys.c b/tty-keys.c
index 27107bb8..59002fb2 100644
--- a/tty-keys.c
+++ b/tty-keys.c
@@ -612,7 +612,8 @@ tty_keys_mouse(const char *buf, size_t len, size_t *size, struct mouse_event *m)
 		return (1);
 	*size = 6;
 
-	log_debug("mouse input is: %.6s", buf);
+	log_debug(
+	    "mouse input: %.6s (%hhu,%hhu/%hhu)", buf, buf[4], buf[5], buf[3]);
 
 	m->b = buf[3];
 	m->x = buf[4];
diff --git a/tty.c b/tty.c
index 72be2c84..92ddf41f 100644
--- a/tty.c
+++ b/tty.c
@@ -402,11 +402,18 @@ tty_update_mode(struct tty *tty, int mode)
 		else
 			tty_putcode(tty, TTYC_CIVIS);
 	}
-	if (changed & MODE_MOUSE) {
-		if (mode & MODE_MOUSE)
-			tty_puts(tty, "\033[?1000h");
-		else
-			tty_puts(tty, "\033[?1000l");
+	if (changed & (MODE_MOUSE|MODE_MOUSEMOTION)) {
+		if (mode & MODE_MOUSE) {
+			if (mode & MODE_MOUSEMOTION)
+				tty_puts(tty, "\033[?1003h");
+			else
+				tty_puts(tty, "\033[?1000h");
+		} else {
+			if (mode & MODE_MOUSEMOTION)
+				tty_puts(tty, "\033[?1003l");
+			else
+				tty_puts(tty, "\033[?1000l");
+		}
 	}
 	if (changed & MODE_KKEYPAD) {
 		if (mode & MODE_KKEYPAD)
diff --git a/window-copy.c b/window-copy.c
index 3b42c456..66402eca 100644
--- a/window-copy.c
+++ b/window-copy.c
@@ -760,17 +760,61 @@ window_copy_mouse(
 {
 	struct window_copy_mode_data	*data = wp->modedata;
 	struct screen			*s = &data->screen;
+	u_int				 i;
+
+	/*
+	 * xterm mouse mode is fairly silly. Buttons are in the bottom two
+	 * bits: 0 button 1; 1 button 2; 2 button 3; 3 buttons released.
+	 *
+	 * Bit 3 is shift; bit 4 is meta; bit 5 control.
+	 *
+	 * Bit 6 is added for mouse buttons 4 and 5.
+	 */
 
-	if ((m->b & 3) == 3)
-		return;
 	if (m->x >= screen_size_x(s))
 		return;
 	if (m->y >= screen_size_y(s))
 		return;
 
-	window_copy_update_cursor(wp, m->x, m->y);
-	if (window_copy_update_selection(wp))
+	/* If mouse wheel (buttons 4 and 5), scroll. */
+	if ((m->b & 64) == 64) {
+		if ((m->b & 3) == 0) {
+			for (i = 0; i < 5; i++)
+				window_copy_cursor_up(wp, 0);
+		} else if ((m->b & 3) == 1) {
+			for (i = 0; i < 5; i++)
+				window_copy_cursor_down(wp, 0);
+		}
+		return;
+	}
+
+	/*
+	 * If already reading motion, move the cursor while buttons are still
+	 * pressed, or stop the selection on their release.
+	 */
+	if (s->mode & MODE_MOUSEMOTION) {
+		if ((m->b & 3) != 3) {
+			window_copy_update_cursor(wp, m->x, m->y);
+			if (window_copy_update_selection(wp))
+				window_copy_redraw_screen(wp);
+		} else {
+			s->mode &= ~MODE_MOUSEMOTION;
+			if (sess != NULL) {
+				window_copy_copy_selection(wp, sess);
+				window_pane_reset_mode(wp);
+			}
+		}
+		return;
+	}
+
+	/* Otherwise i other buttons pressed, start selection and motion. */
+	if ((m->b & 3) != 3) {
+		s->mode |= MODE_MOUSEMOTION;
+
+		window_copy_update_cursor(wp, m->x, m->y);
+		window_copy_start_selection(wp);
 		window_copy_redraw_screen(wp);
+	}
 }
 
 void