file drag and drop to finder apple-tab icon does not bring finder to foreground

I used to be able to show the desktop by hitting a hot corner, grab a file on desktop and hit apple-tab to drag and drop the file to finder's apple-tab icon, which would bring finder to the foreground so I could drop it where I wanted. This does not work anymore. Finder will not come the foreground. This still works for dropping files to other applications...What's the matter?

Thanks!!