Show window 2nd+ time with fade-in transition

Question

Say you have a WS_OVERLAPPEDWINDOW window, and you show it for the first time:

::ShowWindow(hwnd, SW_SHOW);

The window appears with the expected fade-in animation (testing on Windows 10.0.18363).

If you then hide the window:

::ShowWindow(hwnd, SW_HIDE);

and try to re-show it again, with the SW_SHOW call above, it will appear instantly, without the fade-in transition.

The question is: How to make ::ShowWindow() use the fade-in transition when showing the window for the second time?

Note that both the first and subsequent SW_HIDE calls do use the fade-out transition.

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There's an unanswered 5-year old question that asks essentially the same for QT, but since this is a Win32 problem, not specific to QT, I've decided to re-ask it in more general terms.

Answer 1

Based on Sea Coast of Tibet's comment, I did this for a form in my Delphi app called FormPreview:

  FormPreview.Perform(CM_RECREATEWND, 0, 0);
  FormPreview.ShowModal;

Fixed the problem for me where I show and re-show forms.