File: include/views/js/configuration.item.edit.js.php
Starting in line 123
Change of:
if (type == 0 || type == 7 || type == 3 || type == 5 || type == 8 || type == 17)

{ jQuery('#keyButton').prop('disabled', false); }

else

{ jQuery('#keyButton').prop('disabled', true); }

For more small code:
jQuery('#keyButton').prop('disabled', !(type == 0 || type == 7 || type == 3 || type == 5 || type == 8 || type == 17));