This is the most useful keyboard shortcuts that ever existed:

Ctrl + >

In .net framework, if you forget to include a namespace (the using statement on the very top of code, for example: using system), you will receive some compile time errors: some green wiggly line under some objects. For example, if you forget "using System.Data.SqlClient;", when you use "SqlParameter" or "SqlDataReader" in your code, you will see green wiggly lines under SqlParameter and SqlDataReader. Here is the cure: Click the cursor into the words with green wiggly lines, hold Ctrl and press >, it will tell you which namespace you missed. Try it.