I am a newbie to PRONTOedit but I want to warn other newbies that when you hit your DELETE key in Prontoedit be absolutely sure of what you have highlighted! I accidentally deleted an entire device, and the UNDO only put back a part of it, and all aliases to it had vanished. I had to restore from my last save, which I do frequently, fortunately. Prontoedit (or maybe Windows)seems to let several "things" on the screen be highlighted at once but only one is REALLY active. The last thing clicked on in the left window remains bright, even while things on the right side are being worked on, and vica versa. And they don't always coincide. So be careful when you hit that DEL key! ...just hoping to save some grief here.

To help alleviate this problem, don't press the delete key. Instead, use right-click / delete. This way, as long as you know where the mouse is pointing, you'll know you've deleted the correct item.
If it makes you feel any better, I learned this the hard way.