A chart in a tab is much slower than on a standalone screen

Using V8.1, I have a chart component with continuously added values in realtime (similar to EKG). It is extremely fast when placed on a screen but when embedded in a tab control with even just a single tab the performance slows to a fraction.
The code I’m using to create the tab follows.

 lv_obj_t *scr = lv_obj_create(NULL);
 tabView = lv_tabview_create(scr, LV_DIR_TOP, 30);
 tabPid = lv_tabview_add_tab(tabView, "Pid");
  chart = lv_chart_create(tabPid);
  lv_obj_set_size(chart, 240, 100);
  lv_obj_align(chart, LV_ALIGN_TOP_MID, 0, 0);
  lv_chart_set_type(chart, LV_CHART_TYPE_LINE); 
  lv_chart_set_range(chart, LV_CHART_AXIS_PRIMARY_Y, 0, 64);
  lv_obj_set_style_size(chart, 0, LV_PART_INDICATOR);

So I sort of figured out what is going on. Not shown in my code sample is a hidden button matrix I created which occupies a partial area of the tab. If I shrink that down to not encroach on the tab the performance is again good. There must be something in the rendering engine which still “sees” the hidden button matrix when it’s on a tab.


It’s very strange. Hidden objects are skipped very early in the drawing pipeline.
Please enable LV_USE_REFR_DEBUG in lv_conf.h. It will show which areas are redrawn. Do you something suspicious? Or can you send a video about it?