I was informed of a crash on startup by a negative review... Thanks for that. I got no other detail and hadn't seen it myself, until today.
When you quit the CDG Editor it saves the location of the main window and position of the splitter bars in the registry. If you re-order the displays in Windows, the locations it saved become invalid and it screws up the next time you start it.
A simple workaround is to delete the registry key HKLM\Software\DBS\CDGEditor where it stores the window size and location. You might find that when you start it up again the window is very small, just resize it to how you'd like to use it and carry on normally.
I'm not making any promises as to when I'll fix this bug. You can probably tell I've not been terribly active on this project for quite a while.