FindControl什么时候才会使用ObjectFromHWnd函数呢？——VCL很难调试，加一个日志函数，记录时间

IsDelphiHandle
FindVCLWindow
function IsVCLControl(Handle: HWND): Boolean;
function FindControl(Handle: HWND): TWinControl;
function FindVCLWindow(const Pos: TPoint): TWinControl;

function FindControl(Handle: HWnd): TWinControl;
var
  OwningProcess: DWORD;
begin
  Result := nil;
  if (Handle <> 0) and (GetWindowThreadProcessID(Handle, OwningProcess) <> 0) and
     (OwningProcess = GetCurrentProcessId) then
  begin
    if GlobalFindAtom(PChar(ControlAtomString)) = ControlAtom then
      Result := Pointer(GetProp(Handle, MakeIntAtom(ControlAtom)))
    else
      Result := ObjectFromHWnd(Handle);
  end;
end;

function ObjectFromHWnd(Handle: HWnd): TWinControl;
var
  OwningProcess: DWORD;
begin
  if (GetWindowThreadProcessID(Handle, OwningProcess) <> 0) and
     (OwningProcess = GetCurrentProcessID) then
    Result := Pointer(SendMessage(Handle, RM_GetObjectInstance, 0, 0))
  else
    Result := nil;
end;

我测了一下，无论是拖控件放到窗体上，还是动态生成的控件，都是通过GetProp方法取得Delphi对象的指针。那么什么时候会使用神乎其神的ObjectFromHWnd函数呢？

线索还是点击TButton后发生，因为李维的书上提到了这一点～