[support] how to change preview length of article in D7?

[Dave Stevens]

I've seen the "<!--break-->" text insertion but it seems to have no  
efefct, I suppose the text  is too long

-- 
If all the advertising in the world were to shut down tomorrow, would people
still go on buying more soap, eating more apples, giving their children more
vitamins, roughage, milk, olive oil, scooters and laxatives, learning more
languages by iPod, hearing more virtuosos by radio, re-decorating their
houses, refreshing themselves with more non-alcoholic thirst-quenchers,
cooking more new, appetizing dishes, affording themselves that little extra
touch which means so much? Or would the whole desperate whirligig slow
down, and the exhausted public relapse upon plain grub and elbow-grease?

--- Dorothy L Sayers, in Murder Must Advertise