If I see correctly the .mantine-MultiSelect-input element overlap the .mantine-MultiSelect-section element, that is why I could not click the rightSection.
function FilterComponent() {
/* ... */
return (
<MultiSelect
searchable
searchValue={searchValue}
onSearchChange={setSearchValue}
dropdownOpened={dropdownOpened}
data={data}
value={value}
rightSection={
progress > stopped ? (
<Loader size={18} />
) : dropdownOpened ? (
<ActionIcon onClick={() => setDropdownOpened(false)}>
<IconChevronUp size={18} />
</ActionIcon>
) : (
<ActionIcon onClick={() => setDropdownOpened(true)}>
<IconChevronDown size={18} />
</ActionIcon>
)
}
onChange={(val) => setValue(val)}
/>
);
}