if you're using the normal WE and edit the JASS code, the stupid WE would revert to the original GUI code when you hit CTRL+Z...
while on NewGen, CTRL+Z actually includes the edits you made on the script, meaning you undo first the code edits...
so in the end, the script returns back to the original GUI trigger... so you cannot make it something like, convert GUI to JASS ,edit, then hit ctrl+Z to see how it looks like in GUI...