I\'m using omnifunc=pythoncomplete. When autocompleting a word (e.g., os.), I get the list of eligible class members and functions, as
omnifunc=pythoncomplete
os.
If you have the supertab plugin installed, there is an option called supertab-closepreviewonpopupclose.
supertab-closepreviewonpopupclose
Put the following in your .vimrc:
let g:SuperTabClosePreviewOnPopupClose = 1