diff --git a/src/main.c b/src/main.c

index 2cbbbd6..d7e3446 100644

--- a/src/main.c

+++ b/src/main.c

@@ -131,8 +131,11 @@ static void parse_args(int argc, char **argv)

         else if (!strcmp(argv[i], "--tab")) {

             if (i == argc - 1) /* no args left */

                 g_printerr(_("--tab requires an argument\n"));

-            else

-                obc_tab = MAX(atoi(argv[++i]) - 1, 0);

+            else {

+                obc_tab = atoi(argv[++i]) - 1;

+                /* tab number should not be negative */

+                obc_tab = MAX(obc_tab, 0);

+            }

         }

         else

             obc_theme_install = argv[i];