Update events in dialogs?

[qedusa]

I've created a dialog but which I've also manually drawn things to (including a bitmap image). The only problem is, when the dialog is obscured (by another window for example) and then brought back to the front, no updating occurs.
How do I catch the update event in the dialog so I can tell Windows to redraw the dialog contents?

 

[BobbyB]

OnPaint

... class Wizrd -> WM_PAINT