You can examine reactors using the Visual LISP Inspect tool. 
Note: The Visual LISP IDE and ActiveX support is available on Windows only. 
 If you open an Inspect window for a reactor variable, the following information is displayed: 
The items in the Inspect window show the following: 
- Objects owning the reactor 
 
- Event and associated callback function 
 
- Whether or not the reactor is active (yes if added-p is T, no if added-p is nil) 
 
- User data attached to the reactor 
 
- Document range in which the reactor will fire (if 0, it fires only in the context of the drawing document it was created in; if 1, the reactor responds in the context of any document) 
 
- The AutoCAD document attached to the object reactor 
 
Double-click on the item that begins with {Owners} to view a list of the owner objects: 
 Double-click on a list item to obtain detailed information about an owner.