Creating an semi-transparent overlay on a panel to focus on something

I have a panel that displays a list of information. There is a button that you can press to rename the things in this list. I am looking for a way to spawn a new panel that will float above the current panel which will ask for the new name of the item with confirmation/cancel buttons, along with making a shadow overlay on the existing panel that will focus attention to the new panel. Kind of like modal dialogs on websites, or the UAC on Windows.

The new panel spawning would be fairly easy I believe, it’s the shadow / focus effect that I am at a loss at with regards to how to do it. Any ideas?