How to apply "disabled" styling to checkbox text via theme

Description

How to apply “disabled” styling to checkbox text via theme

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

Teensy 4.1 and GCC 9

What LVGL version are you using?

8.0.1

What do you want to achieve?

World domination. And greyed-out checkbox text

What have you tried so far?

Code to reproduce

Using the default theme in 8.0.1, the following:

lv_obj_add_state(btn, LV_STATE_DISABLED);

appears to apply the grey filter to the button and the label associated with the button. However, when the disabled state is applied to a checkbox, only the box itself is affected, not the checkbox text.

The default theme for the button has:

lv_obj_add_style(obj, &styles->disabled, LV_STATE_DISABLED);

but the checkbox has:

lv_obj_add_style(obj, &styles->disabled, LV_PART_INDICATOR | LV_STATE_DISABLED);

Up until now, this makes sense to me, expected behavior. However, if I try adding either of these lines to the checkbox styling in lv_theme_default.c:

lv_obj_add_style(obj, &styles->disabled, LV_PART_MAIN | LV_STATE_DISABLED);
lv_obj_add_style(obj, &styles->disabled, LV_STATE_DISABLED);

It does not have an impact on the checkbox text. What am I missing?

(If I add text_color to &styles->disabled, this is applied to the checkbox text due to the above lines, so I feel like the style is being applied to the checkbox text)