Fix market tracking if no active marker

ui.c

@@ -846,8 +846,9 @@ static UI_FUNCTION_CALLBACK(menu_marker_search_cb)
 static UI_FUNCTION_ADV_CALLBACK(menu_marker_tracking_acb){
   (void)item;
   (void)data;
+  if (active_marker < 0) return;
   if(b){
-    b->icon = (active_marker >=0 && markers[active_marker].mtype & M_TRACKING) ? BUTTON_ICON_CHECK : BUTTON_ICON_NOCHECK;
+    b->icon = markers[active_marker].mtype & M_TRACKING ? BUTTON_ICON_CHECK : BUTTON_ICON_NOCHECK;
     return;
   }
   markers[active_marker].mtype ^= M_TRACKING;