Thread: Disappearing window.

Hello Everyone
This problem might be very obvious but I can't solve it. In my program I have three windows, the main parent window, a child with scroll in the parent window and a child without scroll window in the child with scroll. So I've registered three window classes and I have a separate winproc for each window. I create both child windows in wm_create of the parent winproc. When I run the program the three windows are all in the correct position but when I resize the parent the child with scroll is still visible but the child without scroll has gone, I'm unable to get it visible again. I tried various things and reading more petzold, but still can't work it out.
Thank you for any replies.

Phil

I'm using C .
win2k devC++

I'd suggest to first try using Spy++ (Oh wait, you're not using Visual C++, try Googling for WinSpy) to get the details of your child windows and see what happens to them.

Secondly, I'd hazard a guess and say that there may be a problem with the styles you're using to create the children. Post some code.

Ok here is some of the code

Code:

// Update winclass for main_child window .START
     // Then register class .START
     wndclass.lpfnWndProc     = ChildWndProc;
     wndclass.hIcon           = NULL;
     wndclass.hbrBackground   = (HBRUSH) GetStockObject (LTGRAY_BRUSH) ;
     wndclass.lpszClassName   = szChildClass;
     RegisterClass(&wndclass);
     // Update winclass for main_child window .FINISH
     // Then register class .FINISH

     // Update winclass for child_child window .START
     // Then register class .START
     wndclass.lpfnWndProc     = ChildChildWndProc;
     wndclass.hIcon           = NULL;
     wndclass.hbrBackground   = (HBRUSH) GetStockObject (GRAY_BRUSH) ;
     wndclass.lpszClassName   = szChildChildClass;
     RegisterClass(&wndclass);
     // Update winclass for child_child window .FINISH
     // Then register class .FINISH

and the create child windows. I've tried with and without WS_VISIBLE as the style with showwindow(). Also I made both child handles global to see if it would help.

Code:

hwndChild = CreateWindow(szChildClass, NULL,
                                WS_CHILDWINDOW  | WS_VSCROLL,
                                40,40,360,420,
                                hwnd, (HMENU) 1001,
                                (HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE),
                                 NULL); 
        ShowWindow (hwndChild, SW_SHOW);
          hwndChildChild = CreateWindow(szChildChildClass, NULL,
                                WS_CHILDWINDOW | WS_VISIBLE ,
                                0,0,20,20,
                                hwndChild, (HMENU) 1002,
                                (HINSTANCE) GetWindowLong(hwnd, GWL_HINSTANCE),
                                 NULL);

It could be that the child window is actually still there, but its parent is drawing over it, preventing you from seeing it. Try adding WS_CLIPCHILDREN | WS_CLIPSIBLINGS to the childrens' styles.