The helpfile is deceivingly confusing in this area, as it tells you how to create a @window with /window, and tells how how to rename & title a @window with /renwin, but it doesn't explain how to simply give a @window a custom titlebar-- something that most people would want to do with their custom windows. This is a considerably common question, indeed.
I would suggest that /titlebar @window <topic> be added to the Custom Windows section of the help file, nearby /renwin.
- Raccoon
