add top area threshold

src/slic3r/GUI/Tab.cpp

@@ -1469,6 +1469,8 @@ void TabPrint::build()
         optgroup->append_single_option_line("perimeter_generator");
         //w16
         optgroup->append_single_option_line("top_one_wall_type");
+        //w17
+        optgroup->append_single_option_line("top_area_threshold");
 
         optgroup = page->new_optgroup(L("Fuzzy skin (experimental)"));
         category_path = "fuzzy-skin_246186/#";