I was able to do this and used this all the time in SL. Is there any way to enable this in Lion? I would like to be able to click and hold the icon in the dock to have the app expose initiate.
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Control + down arrow. Then click on the app in the dock.
In Lion the way to activate dock expose is to double tap (not click) the app icon in the dock with two fingers. That is trackpad only so if you are on a desktop without a magic trackpad EDIT: or magic mouse you are out of luck.