Application closing by default?

I seem to be having a simple problem with an application I made. It's just a window with a text box and a couple of straightforward text application things. ~The problem is, any action I preform seems to close the application ~ Save for opening a file, which the program then exits directly after. I thought it was because of a missing break; command, but I couldent find one missing.

Heres the message loop, I'm almost positive the problem is here, but I cant seem to find it;

Code:

<defs>
#define IDR_MENU1   	500

#define ID_FILE_EXIT 	900
#define ID_FILE_NEW  	901
#define ID_FILE_OPEN 	902
#define ID_FILE_SAVE	903
#define ID_FILE_SAVE_AS	904

#define ID_FUNCTION_NEW 100

#define ID_SURFACE_EDIT 200
<defs>

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
 switch(msg) {

  case WM_CREATE:
   TextBoxSetup(hwnd);
   break;

  case WM_SIZE: {		 //WM SIZE START---
   HWND hEdit;
   RECT rcClient;

   GetClientRect(hwnd, &rcClient);

   hEdit = GetDlgItem(hwnd, ID_SURFACE_EDIT);
   SetWindowPos(hEdit, NULL, 0, 0, rcClient.right, rcClient.bottom, SWP_NOZORDER);
  }
  break;			//END OF WM SIZE---



  case WM_COMMAND:		//COMMAND PARSE START---
   switch(LOWORD(wParam)){

    case ID_FILE_EXIT:
     PostMessage(hwnd, WM_CLOSE, 0, 0);
     break;

    case ID_FILE_NEW:
     break;

    case ID_FILE_OPEN:
     OpenFileName(hwnd);
     break;

    case ID_FILE_SAVE:
     break;

    case ID_FILE_SAVE_AS:
     break;

    default:
     break;
  }				//COMMAND PARSE END---

  case WM_CLOSE:
   DestroyWindow(hwnd);
   break;

  case WM_DESTROY:
   PostQuitMessage(0);
   break;

  default:
   return DefWindowProc(hwnd, msg, wParam, lParam);

 }

 return 0;
}

I've been poking around the code for awhile and I just dont see any issues -,-.

Missing break after WM_COMMAND switch.
You also need to indent better. One space is not enough. I recommend at least 4 to make it more readable.
Make sure to match proper indentation with the opening and closing {, to make it easier to read.

Bah! I knew that pesky thing was somewhere. Thanks, I didin't even realize I needed a break; after it.

~I indent with 1 space as a sort of bad habbit, the first time I ever got into coding I was using an old outdated language that required single-space indenting, and I never really got out of that habbit.