Reactors are indeed very active. When you design an application that relies on them, you could very well spend a great deal of time crashing your program and possibly crashing AutoCAD as well. It helps to have a tool available to remove all the reactors you have added, if necessary.
The gpreact.lsp file includes a function gp:clean-all-reactors that does not do much on its own. Instead, it makes a call to the CleanReactors function. Add this function to your utils.lsp file by copying the following code to the end of the file:
;;;--------------------------------------------------------------; ;;; Function: CleanReactors ; ;;;--------------------------------------------------------------; ;;; Description: General utility function used for cleaning up ; ;;; reactors. It can be used during debugging, as ; ;;; well as cleaning up any open reactors before ; ;;; a drawing is closed. ; ;;;--------------------------------------------------------------; (defun CleanReactors () (mapcar 'vlr-remove-all '(:VLR-AcDb-reactor :VLR-Editor-reactor :VLR-Linker-reactor :VLR-Object-reactor ) ) )