When I create a form with auto-generated fields and disable one of them (see code), the field indeed cannot be edited, but the associated spinner remains active (is a numeric field in this case), allowing the modification of the field's value. I believe that the underlying editor of the field (regardless of its type: datepicker, combobox, dropdownlist, numerictextbox or colorpicker) should be disabled when the FormItem is disabled, as it creates inconsistencies in the UI.
<FormItems>
<FormItem Field="@nameof(ViewModel.SomeField)" />
<FormItem Field="@nameof(ViewModel.NumericField)" Enabled="@some_variable"/>
</FormItems>
Regards.
Twain.