Lost: KMail's message list

[Wendell Cochran]

Suddenly KMail opens the mail spool directly where formerly the
message list appeared.  

I can read mail only by scrolling through the lot.  That works, but
it's slow & awkward.

My guess is that I've unknowingly fumblefingered (or misclicked) a
configuration button.  But what & where?

So far I recognize nothing helpful in either the context menus nor
KMail documentation.

That's running
Kubuntu 2.6.22-14
KDE 3.5.8
KMail 1.9.6

Can anyone set me on the right course?

Wendell Cochran
West Seattle