Ограничение зоны перетаскивания форм/окон

Option Explicit
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (pDest As Any, pSource As Any, ByVal ByteLen As Long)
 
Private Sub LetStringArray(sa() As String, idx As Long, sVal As String)
    ' Necessary because, if the array is the function name, you can't assign from within the function.
    sa(idx) = sVal
End Sub
 
Private Function PtrAdd(iPtr As Long, iOffset As Long) As Long
    PtrAdd = (iPtr Xor &H80000000) + iOffset Xor &H80000000
End Function
 
Public Function collAllKeys(c As Collection) As String()
    ' This one actually DOES return vbNullString keys.
    ' Returns 0 to -1 array on empty Collection.
    '
    Dim iArray      As Long
    Dim iItemPtr    As Long
    Dim sKeyTemp    As String
    '
    If c Is Nothing Then
        collAllKeys = Split(vbNullString)
        Exit Function
    End If
    If c.Count = 0 Then
        collAllKeys = Split(vbNullString)
        Exit Function
    End If
    '
    ReDim collAllKeys(1 To c.Count)
    iItemPtr = ObjPtr(c)                                                        ' This works because the offset in the header is also &H18.
    For iArray = 1& To c.Count
        CopyMemory iItemPtr, ByVal PtrAdd(iItemPtr, &H18&), 4&                  ' First/Next item pointer of collection item.
        CopyMemory ByVal VarPtr(sKeyTemp), ByVal PtrAdd(iItemPtr, &H10&), 4&    ' Key string of collection item.
        LetStringArray collAllKeys, iArray, sKeyTemp                            ' Move key into array.
    Next iArray
    '
    ' Mandatory cleanup, put string pointer back to keep memory straight.
    CopyMemory ByVal VarPtr(sKeyTemp), 0&, 4&
End Function
 
Sub afdsfsadf()
    Dim arInp(), arOut(), i&
    
    Dim dict As Object: Set dict = CreateObject("Scripting.Dictionary")
    Dim coll As New Collection
    
    arInp = Array(3, 7, 5, 9, 5, 4, 7)
    For i = 0 To UBound(arInp)
        ' Словарь
        dict(arInp(i)) = Empty
        
        ' Коллекия
        On Error Resume Next
        coll.Add Empty, CStr(arInp(i))
    Next
    
    arOut = dict.keys
    For i = 0 To UBound(arOut)
        Debug.Print arOut(i)
    Next
    
    Debug.Print "--- А теперь тоже самое с помощью коллекции (вот тебе и уникальные числа те же самые) ---"
    
    Dim collKeys() As String
    collKeys = collAllKeys(coll)
    For i = 0 To UBound(collKeys)
        Debug.Print collKeys(i)
    Next
End Sub
 
Private Sub Form_Load()
    afdsfsadf
End Sub