Problem with non-functional window

I'm having a problem with this program. When I run it, I can interact with the buttons and text-edit-window, but I cannot interact with the "outer" controls, ie X-button, minimize button, resize window, move window etc...
It's probably a simple obvious error, but I can't find it...

Code:

---

//*** Included Files ***
#include <windows.h>
#include "TextEdit.h"


//*** Message Handler ***
LRESULT MessageHandler(HWND WinHandle, UINT Message, WPARAM wParam, LPARAM lParam)
{
  //Do stuff
  switch(Message)
  {
      //Interaction with buttons
      case WM_COMMAND:
        switch(LOWORD(wParam))
        {
            //Press the button EXIT
            case SystemExit:
              DestroyWindow(WinHandle);
            break;
        }
      break;
      //Window shutdown has been activated (X or EXIT)
      case WM_CLOSE:
        DestroyWindow(WinHandle);
      break;
      //Window has been destroyed (See above)
      case WM_DESTROY:
        PostQuitMessage(0);
      break;
      default:
        //In case message didn't get handled, do default handling
        return DefWindowProc(WinHandle, Message, wParam, lParam);
  }

  //Return success
  return 0;
}


//*** Creates A Window ***
void SetupWindow(HINSTANCE CurInst)
{
  //Creates a handle window
  HWND HandleWindow;

  //Create the window object (modeless)
  HandleWindow=CreateDialog(CurInst, MAKEINTRESOURCE(MainForm), NULL, (DLGPROC)MessageHandler);

  //Make the window appear
  ShowWindow(HandleWindow, SW_SHOW);
}


//*** Win Main ***
int WINAPI WinMain(HINSTANCE CurInst, HINSTANCE PrevInst, LPSTR ParList, int WinShowType)
{
  //Data
  MSG Message;
  BOOL ProgramStatus=TRUE;

  //Creates a window
  SetupWindow(CurInst);

  //Main loop
  while(ProgramStatus==TRUE)
  {
      if(PeekMessage(&Message, NULL, 0, 0, PM_REMOVE))
      {
        //Message processing
        if(Message.message==WM_QUIT) ProgramStatus=FALSE;
        TranslateMessage(&Message);
        DispatchMessage(&Message);
      }
      else
      {
        //Idle
      }
  }

  //Exit
  return 0;
}

---

in your MessageHandler():
...
case WM_COMMAND:
blahblah
break;
blahblah
default:
return DefWindowProc();
}
return 0;
...

when WM_COMMAND message you are not handling occurs, handler would break; and return 0;, not DefWindowProc(). Isn't that the problem :)?

PS: sorry for how is my post formatted ;)

Ahhh, that's true :). Thanks!

...Hmm, that wasn't the problem after all... :(. Still non functional.
(PS: I've updated my code above)

Take the DefWindowProc() out of the WM_COMMAND switch.

Ensure the dialog has the System Menu style checked or WS_SYSMENU style.

Why are you using PeekMesage() rather than GetMessage()/

(or if not the main Dlg IsDialogMessage() )