Active Choice radio parameter on parambuild page is always visible as text box (which is fine). Unfortunately, the default value is set incorrectly. The plugin always fills the text box with the first value from the script and does not remove :selected suffix. It means that for the following script:

['1', '2', '3:selected', '4', '5']

it returns 1, and for:

['1:selected', '2', '3', '4', '5']

it returns 1:selected.

This behavior makes radio button unusable when builds are triggered by Jenkins Pipeline build step or parambuild/buildWithParameters URLs.