I’ve checked many sample project for tizen native app, the conformant widget was always as the first(and only) child of the main window, as below code. /* Conformant */ ad->conform = elm_conformant_add(ad->win); elm_win_indicator_mode_set(ad->win, ELM_WIN_INDICATOR_SHOW); elm_win_indicator_opacity_set(ad->win, ELM_WIN_INDICATOR_OPAQUE); evas_object_size_hint_weight_set(ad->conform, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND); elm_win_resize_object_add(ad->win, ad->conform); evas_object_show(ad->conform); I want to know its background design concepts for the ui app, is the direct child of a window must to be a conformant widget and why? Or did the window can have other children except the conformant?