The Invalid Actions and Invalid Conditions options in Decision Table Creator are likely features that allow you to view and identify any actions or conditions in your decision table that may be invalid or not meeting the specified criteria. When you select either of these options, the software likely highlights all actions or conditions that it considers to be invalid, so that you can review and make any necessary changes.
It is possible that the software is using a default evaluation to determine which actions or conditions are invalid, but without more information about the specific software you are using, it is difficult to say for sure.
In general, most software can be extended or customized through the use of plugins or extensions. However, whether or not a particular piece of software can be extended would depend on the specific features and capabilities of that software. It would be best to consult the documentation or support resources for the Decision Table Creator software to see if it has any options for extending its functionality.