Cannot submit an empty value in Explode limit

Hey,

I am using Explode to create an array of value.
For the Limit field, here is the description :

"If limit is set and positive, the returned items will contain a maximum of limit with the last item containing the rest of string. If limit is negative, all components except the last -limit are returned. If the limit parameter is zero, then this is treated as 1. If limit is not set, then there will be no limit on the number of items returned."

However, when I try to submit the form is an empty value, the field is automatically saved with 0 in it.

The "empty" value option is not usable as the configuration form saving prevents it.