I'm using `omnifunc=pythoncomplete`. When autocompleting a word (e.g., `os.<something>`), I get the list of eligible class members and functions, as expected, as well as a scratch buffer preview window with documentation about the selected member or function. This is great, but after selecting the function I want, the preview window remains. 

I can get rid of it with `:pc`, but I'd like it just to automatically disappear after I've selected my function, a la Eclipse. I've played around with `completeopt` but to no avail.