Allow Custom Response for Checkboxes

[shurco]

It would be more logical to add an "Allow custom response" option for the "Checkboxes" form type. For instance, there are situations when a user selects from the available answer options, but they have their own variant and wish to add it.

[PhilReinking]

Honestly I first thought we have this already. But seems it is also activated for the radio input type. Will also add it to the checkbox input :)