IntOption supports only positive values?

If I create options for an IntOption field with positive values, I can select them. If I create options with 0 or negative values, I cannot select them. Is this by design or a bug?

Litium version: 7.2.3

I tested this in Litium 7.2.3, but it works for me, see below. Added it as a product field.
image

Options for the field:
image

Is your setup different?

There seems to be an display issue with 0 in particular. I’ve reported it as a bug https://docs.litium.com/support/bugs/bug_details?id=49081