Lvgl object can not show horizon scrollbar


I have been struggling for about two weeks for this strange problem. Actually I have port lvgl to many different projects & boards during these years. Now I am working on a new RTOS with multi-task execution enviroment. The problem is i can not make the basic widgets horizontal scrollbar show up after I ported the latest V8.3.1 lvgl.

What MCU/Processor/Board and compiler are you using?

D1s CPU which is a RISC-V 64bit CPU

What LVGL version are you using?

LVGL V8.3.1

What do you want to achieve?

I want to port lvgl v8.3.1 to a new board and show basic widgets

What have you tried so far?

I have tried basic tabview demo , basic object demo, but to find horizon scroll bar will never shows up, but vertical scroll-bar is always ok to show,

Code to reproduce

Just create a basic object and i expected to see scrollbar in both vertical & horizon directions. But
I can only see vertical ones.

/* Basic Object on Screen */
static void lv_example_my(void)
   lv_obj_add_event_cb(lv_scr_act(), scr_event_cb, LV_EVENT_ALL, NULL);
    lv_obj_t * obj1;
    obj1 = lv_obj_create(lv_scr_act());
    lv_obj_set_size(obj1, 400, 400);
   lv_obj_align(obj1, LV_ALIGN_CENTER, 0, 0);

Screenshot and/or video

although I don’t know why you want to see horizon scroll bar,
but if you create object which is child of obj1 such as button and set position to larger one than size of obj1 (400, 400), you may see the scroll bar.