If you have you Dock set to automatically show and hide, you make have noticed that occasionally it refuses to appear when you are dragging an icon onto it. This drives me crazy when I am trying to eject disk images. I drag the icon down to the bottom of the screen, but the Dock simply doesn't appear. Normally my solution is to give up, right-click on the icon and choose eject, which takes far too long. While looking for a better way, I found a brilliant tip on the MacTipper blog.

Simply use the keyboard shortcut Command-Option-D, which turns on/off Dock hiding. You don't even have to stop dragging your icon to do this, and it works whatever application you are in.

Next time the Dock fails to appear, while still dragging your icon, simply hit Command-Option-D and the Dock should spring up. Drop your icon onto the trash (or eject icon, or whatever you want), and then just hit Command-Option-D again to make the Dock disappear again.