Implement "Whats This" using Win32

I want to implement "whats this" functionality as seen in most of windows programs. For example -> When you

right click on desktop and select properties and when u again right click on the properties dialog you get a

pop up menu with "whats this". When i click on that u get a timy description of that part of the dialog. How do

i do that. Can you give me an example program. How do you implement "whats this" in a win32 program using

windows api. Is there any example program on the net with source code using which i can learn to implement it

in my program.

Try here. It's under the first parameter of the CreateWindowEx function (I think that's what you're looking for...)

Chris