I have problem in demo project

The demo project is from \lv_examples\lv_apps\demo
I modified some code, and it’s normal, part of code below:
lv_obj_t *scr = lv_disp_get_scr_act(NULL); /Get the current screen/

    static lv_style_t style_tv_btn_bg;
    lv_style_copy(&style_tv_btn_bg, &lv_style_plain);
    style_tv_btn_bg.body.main_color = lv_color_hex(0x487fb7);
    style_tv_btn_bg.body.grad_color = lv_color_hex(0x487fb7);
    style_tv_btn_bg.body.padding.top = 0;
    style_tv_btn_bg.body.padding.bottom = 0;

    static lv_style_t style_tv_btn_rel;
    lv_style_copy(&style_tv_btn_rel, &lv_style_btn_rel);
    style_tv_btn_rel.body.opa = LV_OPA_TRANSP;
    style_tv_btn_rel.body.border.width = 0;

    static lv_style_t style_tv_btn_pr;
    lv_style_copy(&style_tv_btn_pr, &lv_style_btn_pr);
    style_tv_btn_pr.body.radius = 0;
    style_tv_btn_pr.body.opa = LV_OPA_50;
    style_tv_btn_pr.body.main_color = LV_COLOR_WHITE;
    style_tv_btn_pr.body.grad_color = LV_COLOR_WHITE;
    style_tv_btn_pr.body.border.width = 0;
    style_tv_btn_pr.text.color = LV_COLOR_GRAY;

    lv_obj_t * tv = lv_tabview_create(scr, NULL);
    lv_obj_set_size(tv, LV_HOR_RES_MAX, LV_VER_RES_MAX);
#if LV_DEMO_WALLPAPER
    lv_obj_t * wp = lv_img_create(scr, NULL);
    extern lv_img_dsc_t img_bubble_pattern;
    lv_img_set_src(wp, &img_bubble_pattern);
    lv_obj_set_width(wp, LV_HOR_RES_MAX * 3);
    lv_obj_set_protect(wp, LV_PROTECT_POS);

    lv_obj_set_parent(wp, ((lv_tabview_ext_t *) tv->ext_attr)->content);
    lv_obj_set_pos(wp, 0, -5);
#else
    /*Blue bg instead of wallpaper*/
    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BG, &style_tv_btn_bg);
#endif

    lv_obj_t * tab1 = lv_tabview_add_tab(tv, "Write");
    lv_obj_t * tab2 = lv_tabview_add_tab(tv, "List");
    lv_obj_t * tab3 = lv_tabview_add_tab(tv, "Chart");
lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_BG, &style_tv_btn_bg); lv_tabview_set_style(tv, LV_TABVIEW_STYLE_INDIC, &lv_style_plain); lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_REL, &style_tv_btn_rel); lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_PR, &style_tv_btn_pr); lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_TGL_REL, &style_tv_btn_rel); lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_TGL_PR, &style_tv_btn_pr);
    write_create(tab1);
    //!list_create(tab2);
    //!chart_create(tab3);

#if LV_DEMO_SLIDE_SHOW
    lv_task_create(tab_switcher, 3000, LV_TASK_PRIO_MID, tv);
#endif

Then I modified the code for the bold part, the text area is disappeared,
Here is the code for the bold part that I modified:

        lv_obj_t * tab1 = lv_tabview_add_tab(tv, "Write");
        lv_obj_t * tab2 = lv_tabview_add_tab(tv, "List");
        lv_obj_t * tab3 = lv_tabview_add_tab(tv, "Chart");

    #if LV_DEMO_WALLPAPER
        lv_obj_t * wp = lv_img_create(scr, NULL);
        extern lv_img_dsc_t img_bubble_pattern;
        lv_img_set_src(wp, &img_bubble_pattern);
        lv_obj_set_width(wp, LV_HOR_RES_MAX * 3);
        lv_obj_set_protect(wp, LV_PROTECT_POS);

        lv_obj_set_parent(wp, ((lv_tabview_ext_t *) tv->ext_attr)->content);
        lv_obj_set_pos(wp, 0, -5);
    #else
        /*Blue bg instead of wallpaper*/
        lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BG, &style_tv_btn_bg);
    #endif

Is it a bug?

First of all, you should enclose code snippets in ```c and ``` tags.

Second, please describe what isn’t working. “It doesn’t work” is not enough information for us to find the issue.

I am sorry that I have not expressed clearly
Here is the code:

void demo_create(void)
{
    lv_coord_t hres = lv_disp_get_hor_res(NULL);
    lv_coord_t vres = lv_disp_get_ver_res(NULL);

    static lv_style_t style_tv_btn_bg;
    lv_style_copy(&style_tv_btn_bg, &lv_style_plain);
    style_tv_btn_bg.body.main_color = lv_color_hex(0x487fb7);
    style_tv_btn_bg.body.grad_color = lv_color_hex(0x487fb7);
    style_tv_btn_bg.body.padding.top = 0;
    style_tv_btn_bg.body.padding.bottom = 0;

    static lv_style_t style_tv_btn_rel;
    lv_style_copy(&style_tv_btn_rel, &lv_style_btn_rel);
    style_tv_btn_rel.body.opa = LV_OPA_TRANSP;
    style_tv_btn_rel.body.border.width = 0;

    static lv_style_t style_tv_btn_pr;
    lv_style_copy(&style_tv_btn_pr, &lv_style_btn_pr);
    style_tv_btn_pr.body.radius = 0;
    style_tv_btn_pr.body.opa = LV_OPA_50;
    style_tv_btn_pr.body.main_color = LV_COLOR_WHITE;
    style_tv_btn_pr.body.grad_color = LV_COLOR_WHITE;
    style_tv_btn_pr.body.border.width = 0;
    style_tv_btn_pr.text.color = LV_COLOR_GRAY;

    lv_obj_t * tv = lv_tabview_create(lv_disp_get_scr_act(NULL), NULL);
    lv_obj_set_size(tv, hres, vres);

    lv_obj_t * tab1 = lv_tabview_add_tab(tv, "Write");//!1

    lv_obj_t * wp = lv_img_create(lv_disp_get_scr_act(NULL), NULL);
    extern lv_img_dsc_t img_bubble_pattern;
    lv_img_set_src(wp, &img_bubble_pattern);
    lv_obj_set_width(wp, hres * 4);
    lv_obj_set_protect(wp, LV_PROTECT_POS);

    lv_obj_set_parent(wp, ((lv_tabview_ext_t *) tv->ext_attr)->content);
    lv_obj_set_pos(wp, 0, -5);

    //lv_obj_t * tab1 = lv_tabview_add_tab(tv, "Write");//!2

    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_BG, &style_tv_btn_bg);
    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_INDIC, &lv_style_plain);
    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_REL, &style_tv_btn_rel);
    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_PR, &style_tv_btn_pr);
    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_TGL_REL, &style_tv_btn_rel);
    lv_tabview_set_style(tv, LV_TABVIEW_STYLE_BTN_TGL_PR, &style_tv_btn_pr);

    write_create(tab1);
}

The problem is that the text area is not displayed on the screen.
Here is the screen short

In the second example, you add the tab before you create the wallpaper background. Since, by default, objects are positioned relative to their creation order, the wallpaper is on top of the text box.