Fibonacci and progressbar

I have a dialog which has a button and a textbox to input a number
When I press the button on the main dialog, a new digalog will be displayed with DoModal() along with a progress bar on it to indicate the process of calulation.

The progress bar runs :( fine but the dialog itself won't dissappear after computing the Fib(inputnumber) :(
I send a WM_CLOSE message in the worker thread and this closes not only the progress dialog itself but the main dialog as well :(

Thank you

You're probably sending WM_CLOSE to your main dialog instead of the child dialog.
Check the hWnd parameter of SendMessage/PostMessage.