diff --git a/src/mn_setup.c b/src/mn_setup.c
index 1eb8d7b65..b8bfa26a8 100644
--- a/src/mn_setup.c
+++ b/src/mn_setup.c
@@ -4212,6 +4212,8 @@ static boolean NextPage(int inc)
     return true;
 }
 
+static setup_menu_t *active_thermo = NULL;
+
 boolean MN_SetupResponder(menu_action_t action, int ch)
 {
     // phares 3/26/98 - 4/11/98:
@@ -4460,6 +4462,7 @@ boolean MN_SetupResponder(menu_action_t action, int ch)
         set_weapon_active = false;
         default_verify = false;              // phares 4/19/98
         print_warning_about_changes = false; // [FG] reset
+        active_thermo = NULL;
         M_StartSound(sfx_swtchx);
         return true;
     }
@@ -4526,8 +4529,6 @@ boolean MN_SetupMouseResponder(int x, int y)
         return true;
     }
 
-    static setup_menu_t *active_thermo = NULL;
-
     if (M_InputDeactivated(input_menu_enter) && active_thermo)
     {
         int flags = active_thermo->m_flags;