I'm really enjoying using gnus as my mail reader, but I have one gripe. If I have a split (say I'm working on some code in the left buffer when gnus groups opened in the right) and open a summary buffer for my INBOX, it takes over the entire frame. Is there a setting somewhere to tell gnus to simply open the summary in the right-hand buffer so I can still see my code buffer on the left?
You can set gnus-use-full-window to nil, as mentioned in the "Window Layout" section of the Gnus manual. Note the warning, though:
Setting this variable to `nil' kinda works, but there are glitches. Use at your own peril.