A proof is a type of shell that has the word "Proof" on top and no other special functionality. The LDE will treat it as a container with things inside that should be validated.

It also provides a context menu item (no matter where inside the proof the user right-clicked) that lets the user ask to run validation only for this proof. The implementation for that is to send the exact same validation request to the deductive engine, except adding a "target=true" attribute to the environment for this proof. The engine will recognize that attribute and send feedback only for the proof environment marked with that attribute.