Widgets (Buttons etc.) with Monochrome Display not displayed


Hello, i have a monochome E-Paper Display and I´m trying to use it with LVGL. Right now I have a Problem with the Widgets. I try to get a Button in order to get Touch working. But when I try to Display the Button (lv_example_btn_1) the screen stays empty. It`s the same problem with the arc example. When I use the the keyboard theres most things displayed, but I think its missing the Text-Area. I can display Pictures without Problems as well.

Does someone has an Idea what I´m doing wrong? I have a Picture from the Keyboard Example:

And I also modified the following Label Example like this:

    lv_obj_t * label1 = lv_label_create(lv_scr_act());
    lv_label_set_long_mode(label1, LV_LABEL_LONG_WRAP);     /*Break the long lines*/
    lv_label_set_recolor(label1, true);                      /*Enable re-coloring by commands in the text*/
    lv_label_set_text(label1, "#0000ff Re-color# #ff00ff words# #ff0000 of a# label, align the lines to the center "
                      "and wrap long text automatically.");
    lv_obj_set_width(label1, 150);  /*Set smaller width to make the lines wrap*/
    lv_obj_set_style_text_align(label1, LV_TEXT_ALIGN_CENTER, 0);
    lv_obj_align(label1, LV_ALIGN_CENTER, 0, -40);

    lv_obj_t * label2 = lv_label_create(lv_scr_act());
    lv_label_set_long_mode(label2, LV_LABEL_LONG_SCROLL_CIRCULAR);     /*Circular scroll*/
    lv_obj_set_width(label2, 150);
    lv_label_set_text(label2, "It is a circularly scrolling text. ");
    lv_obj_align(label2, LV_ALIGN_CENTER, 0, 40);

    lv_obj_t * button = lv_btn_create(lv_scr_act());
    lv_obj_set_size(button, 100, 30);
    //lv_obj_set_text(button, "It is a circularly scrolling text. ");
    lv_obj_align(button, LV_ALIGN_CENTER, 0, 80);

But only this is the Result:

As I said with a few other examples I tried it was just white Screen. The LVGL Mono Theme in the config file is activated.

Thanks in advance!

Does someone has an Idea what I did wrong? I`m still looking for a solution. Is there a feature to load bitmaps as background for buttons etc? But it would be much nicer to have the integrated widgets working in monochrome as well. At least the most important widgets…
The framebuffer is one bit per pixel. I used a version of a pixel callback to achieve this. could the problem come from this?

Im using LVGL 8.3, forgot to mention this. Ive found some clue that i have to do a init in order to use the monochrome theme.

Ive found this: `

lv_theme_t * th= lv_theme_mono_init(210, NULL);


But I get the following Error Message: too few arguments to function ‘lv_theme_mono_init’

So does anyone has another Idea how to get Buttons/Widgets to work on a monochrome display?