How to change the Button focused border color after added into one group

Hello,
We use lvgl v7.0 to create one button with keypad controller. we hope the button can’t be seen by user. So we set the button focused border width as 0 and OPA as 0.
static lv_style_t style_screen_info_btnMenu_main_focused;
lv_style_reset(&style_screen_info_btnMenu_main_focused);
lv_style_set_text_color(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, lv_color_hex(0xFF0000));
lv_style_set_text_font(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, &lv_font_montserrat_12);
lv_style_set_bg_opa(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, 0);
lv_style_set_border_width(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, 0);
lv_style_set_border_opa(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, 0);
lv_style_set_border_color(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, lv_color_hex(0x000000));
lv_style_set_radius(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, 50);
lv_style_set_shadow_width(&style_screen_info_btnMenu_main_focused, LV_STATE_FOCUSED, 0);
lv_obj_add_style(ui->screen_info_btnMenu, LV_BTN_PART_MAIN, &style_screen_info_btnMenu_main_focused);
It is ok to hidden and user can’t see it before added into lv_group_t. But we can see the button border width is set to 2 and color as red after added into group for responding keypad.
lv_obj_set_event_cb(ui->screen_info_btnMenu, screen_info_btnMenu_event_handler);
lv_group_add_obj(pKeyGroup, ui->screen_info_btnMenu);

how to change the button focused border color and width after added into group? thanks.