Select Case uMsg
    Case WM_ENTERSIZEMOVE 
        SizeMoving = True
    Case WM_EXITSIZEMOVE 
        If SizeMoving Then EXITSIZEMOVE_Proc
        SizeMoving = False
.....

Private Sub EXITSIZEMOVE_Proc()
    Dim mRect As RECT
    SendMessage Frm.hwnd, WM_SETREDRAW, True, 0
    GetClientRect Frm.hwnd, mRect
    RedrawWindow Frm.hwnd, mRect, 0&, RDW_ERASE Or _
        RDW_INVALIDATE Or RDW_UPDATENOW Or RDW_ALLCHILDREN = &H80
    .......