WM_PAINT logic

[Paul McKenzie]

Why doesn't the entire client area become invalidated after scroll bar moves by clicking once on the down arrow? Doesn't the entire client area need to be repainted?

Are you using your debugger? If you are, there is a caveat that I didn't mention.

If you're debugging a WM_PAINT message, then it is advantageous to have a dual monitor setup -- one monitor has the debugger, the other has the output of your app. The reason why is that setting breakpoints in the debugger, and then running your app on a single monitor may cause the WM_PAINT message to be generated many times than necessary when your debugger pops up on the screen.

Either you have a dual monitor setup, or you have to size the app window to make sure it doesn't interfere with your debugger screen (a pain in the neck, but that's what I've used to debug WM_PAINT messages).

Regards,

Paul McKenzie