Problem with game freeze after ALT+TAB

[HerMajestyDrMona]

Hi. In Empire Earth II many users are complaining that sometimes game freezes after ALT+TAB. We use d3d8to9 (with little modifications, but I restored the official d3d8to9 release version for tests).

I detected, that the freeze occurs in function:

HRESULT STDMETHODCALLTYPE Direct3DDevice8::Reset(D3DPRESENT_PARAMETERS8 *pPresentationParameters)

Exactly at step:

ProxyInterface->Reset(&PresentParams);

In my pseudo-log it looks following:

Mona Reset returned at: 2021-11-07_00.56.43.189 after: 113 milliseconds. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 0152198A
Mona Calling Reset at: 2021-11-07_00.56.43.756. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 0152198A
Mona Reset returned at: 2021-11-07_00.56.43.864 after: 108 milliseconds. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 0152198A
Mona Calling Reset at: 2021-11-07_00.56.44.413. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 0152198A
Mona Reset returned at: 2021-11-07_00.56.44.512 after: 99 milliseconds. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 0152198A
Mona Calling Reset at: 2021-11-07_00.56.45.668. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 0152198A
Mona Reset returned at: 2021-11-07_00.57.25.812 after: 40144 milliseconds. HWND: 0152198A. Iconic: 0. Active window: 0152198A. Foreground window: 00092AF6

As you can see, it usually returns after ~100 milliseconds. However, sometimes it takes 40144+ milliseconds.
I believe that there is some fixed timeout in function ProxyInterface->Reset(&PresentParams) which is 40 seconds.

I wonder what could be the problem? Is there any possibility to figure out what goes wrong?
I noticed that with DirectX 8, the Reset() function finishes much faster. I mean, instantly after ALT+TAB I can see the game window. With d3d8to9 it takes a moment to show the screen (from black). I wonder if there is some extra check available, that would determine if Reset() is needed? Or maybe this game expect some different reset method?
The ALT+TAB bug is not easily easily reproducible. It happens randomly, usually after fast spamming of ALT+TAB key. The only thing I'm 100% sure about is that freeze occurs at that Reset function from DirectX 9.

Any help and tips would be very welcome!

EDIT:
I forgot to mention that the problem seems to only occur on computers with Nvidia graphics card. I personally am not able to reproduce this bug on my laptop with integrated AMD card, only on Desktop PC with RTX2070.

[HerMajestyDrMona]

Problem solved!

Seems like once again Windows 10 / 11 "Fullscreen optimizations" cause the problem.

I believe that there is something broken in Nvidia drivers, because it looped at some .dll file from Nvidia.

Either way, checking option "Disable fullscreen optimizations" fixed it fully. I wish I remembered earlier about this option :(