// Create an instance of LLComboBox LLComboBox* combo_box = new LLComboBox(parent_view, name, rect, tooltip); // Add options to the combo box combo_box->add("Option 1"); combo_box->add("Option 2"); combo_box->add("Option 3"); // Set the selected option combo_box->setCurrentByIndex(1); // sets "Option 2" as the selected optionThe LLComboBox class is a part of the Linden Lab Second Life Viewer API or library.