diff --git a/tracks.c b/tracks.c
index 6948b42..0579d4b 100644
--- a/tracks.c
+++ b/tracks.c
@@ -2267,6 +2267,7 @@ static char *interpret_move(const game_state *state, game_ui *ui,
 
         if (!INGRID(state, gx, gy)) {
             /* can't drag from off grid */
+            ui->drag_sx = ui->drag_sy = -1;
             return NULL;
         }