Checkboxes not Checking?

I have a dialog box with a check box
When the user clicks on the checkbox, it does not check. Why? I noticed that if I make the code check a different checkbox than the one thats being clicked, it works
Here is my dialog code

Code:

HWND Signon;
BOOL CALLBACK SomeDlgProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
    switch(Message)
    {
        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
                case IDC_CHK_AUTO:
                {
                    SendDlgItemMessage(Signon, IDC_CHK_AUTO, BM_SETCHECK, BST_CHECKED, 0);
                    break;
                }
                case WM_CLOSE:
                case WM_DESTROY:
                    DestroyWindow(Signon);
                    break;
            }
        break;
        default:
            return FALSE;
    }
    return TRUE;
}

comment out:
SendDlgItemMessage(Signon, IDC_CHK_AUTO, BM_SETCHECK, BST_CHECKED, 0);

Tried it and didn't work

I should probably add that my control resource thing is this:

Code:

  CHECKBOX "Auto", IDC_CHK_AUTO, 6,49,150,9

Use the BS_AUTOCHECKBOX style.

Code:

  CHECKBOX "Auto", IDC_CHK_AUTO, 6,49,150,9, BS_AUTOCHECKBOX | WS_TABSTOP

Works now, thanks!