add "Close Button" to the up-right side of the window

hi every1,

i try to do somthing, to add "Close Button" to the up-right side of the page - but just to 1 page, not all the pages!!!
i tried to use:
user32::GetWindowLong & user32::SetWindowLong to change to window style (and to add WS_SYSMENU to the style)
and it worked!
but the problem is that i don't know how to do refresh to the window ...

thanks for your help!!

try RedrawWindow with the RDW_FRAME|RDW_ERASE|RDW_INTERNALPAINT|RDW_INVALIDATE| RDW_ERASENOW flags