Most developers have experienced the intellisense window popping up and hiding code you still need to see or reference. In the past, you had to close the intellisense window to see your code but Visual Studio 2008 has added a nice feature that lets you temporarily hide the intellisense window. Now when the intellisense window pops up you can press the Ctrl key to temporarily set the opacity to 10% on the intellisense window so you can see your code behind it. When you release the Ctrl key, the intellisense window opacity goes back to 100%.
Intellisense window showing as normal.

Intellisense window hidden while Ctrl key is pressed.
