error when suspending gnus and others

[Sebastian Luque]

It's been a long time that I've gotten around this error by burying the
buffer, instead of using the proper function provided by gnus and other
applications. This error shows up when doing gnus-group-suspend, and in
other applications that call delete-frame(). Below is the backtrace I get:

,-----[ *Backtrace* (lines: 1 - 10) ]
| Debugger entered--Lisp error: (error "Attempt to delete the sole visible or 
iconified frame")
|   delete-frame()
|   (if (one-window-p) (delete-frame) (old-delete-window (selected-window)))
|   delete-window(#<window 158 on *Group*>)
|   (while (setq win (get-buffer-window buffer frame)) (delete-window win))
|   (let (win) (while (setq win ...) (delete-window win)))
|   delete-windows-on(#<buffer *Group*> t)
|   gnus-group-suspend()
|   call-interactively(gnus-group-suspend)
`-----

I suspect I have a variable that is not set to the correct value. Can
somebody please suggest what it might be?

-- 
Sebastian Luque