Rectangle doesn't have corners ( drawn more like a cylinder)

I been testing LVGL on windows and i am trying to draw a rectangle on screen however the corners are always round .
The code is straight forward :

    lv_init();
    lv_display_t * display = lv_windows_create_display(title, 512 , 256, 100, FALSE, FALSE);
    lv_windows_acquire_pointer_indev(display);
    /*Initialize the HAL for LVGL*/
    lv_obj_t * scr = lv_obj_create(NULL) ;
    lv_obj_set_style_bg_color(scr ,lv_color_black(),0);
    lv_disp_load_scr(scr);
    lv_obj_t * my_rect = lv_obj_create(lv_scr_act());
    lv_obj_set_size(my_rect ,50,10);
    lv_obj_set_pos(my_rect ,100,100);
    lv_obj_set_style_bg_color(my_rect ,lv_color_white(),0);

I suspect that this has to do with Styles , however adding lv_obj_remove_style_all(my_rect) after creating my_rect object , will no longer show my rectangle on screen .

Thank you in advance for your help !

Add the command at the end
lv_obj_set_style_radius(my_rect, 0, LV_PART_MAIN);

Thank you for your help , it resolved the issue .
Is there a page in the Documentation I could’ve read that explains this ?Does the LV_PART_MAIN style have by default a Radius ?
To which structure does this Raduis parameter belong ? lv_style_t ?

Hello,

it’s part of the default theme. See: Styles — LVGL documentation

And the default theme definition file: lvgl/src/themes/default/lv_theme_default.c at master · lvgl/lvgl · GitHub

This is also why the rectangle is blue by default, and the text white.