It is possible to modify the demonstration programs using the built in editor. To do this, you must first make sure that you have loaded an application and that you are NOT in the stepping mode. To edit the code select the File -> Edit option which will call up the edit and load the source code from the currently loaded application. Edit the code in the usual way and then scroll to the bottom of the screen and click the SAVE button. This will save the file and automatically call the Compile with args.. option. This will occur even if the program doesn't use command line arguments, in which case you should leave the text field balnk. Click compile and the jvmrlo will recompile your program after which you can run or step through it. If there are any compiler error you will receive an error message and returned to the Editor. After re-editing and saving the code you will need to select File -> Compile to manually compile the code before proceeding.