Don't create an undo-chain entry for a move with no effect.

[originally from svn r7333]

1 files changed, 6 insertions, 2 deletions

diff --git a/filling.c b/filling.c
index ac5b6d9..82efcca 100644
--- a/filling.c
+++ b/filling.c
@@ -962,9 +962,13 @@ static char *interpret_move(game_state *state, game_ui *ui, game_drawstate *ds,
     {
         const int i = w*ui->y + ui->x;
         char buf[64];
-        sprintf(buf, "%d_%d", i, button);
         ui->x = ui->y = -1;
-        return dupstr(buf);
+	if (state->board[i] == button) {
+	    return "";		       /* no change - just update ui */
+	} else {
+	    sprintf(buf, "%d_%d", i, button);
+	    return dupstr(buf);
+	}
     }
 }