Windows 11 – Different behavior of SW_SHOWMAXIMIZED in multi-monitor MFC application

Question

Windows 11 – Different behavior of SW_SHOWMAXIMIZED in multi-monitor MFC application

Siji, Merlin 0

We have an MFC MDI application running in a multi-monitor setup.

On Windows 10, minimizing the application and restoring it via taskbar click correctly maximizes it across all monitors.

Starting with Windows 11 23H2, after minimizing the application, clicking the taskbar icon does not restore/maximize it across all monitors.

In OnSysCommand, we handle SC_RESTORE as follows:

if (nID == SC_RESTORE)

If SW_SHOWMAXIMIZED is replaced with SW_RESTORE, the behavior works correctly on Windows 11. However, our application relies on SW_SHOWMAXIMIZED in multiple other places, so making this change is not straightforward.

Has there been a change in window management behavior in Windows 11 23H2 that affects SW_SHOWMAXIMIZED during SC_RESTORE?

Is there a recommended approach for maximizing windows across multiple monitors in Windows 11?

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Siji, Merlin 0

if (nID == SC_RESTORE)

{

for (int i = 0; i < NoOfMainFrmAlive; ++i)

{

    PvMonitor* pMonitor = (PvMonitor*)m_MainFrameArr.GetAt(i);

    if (pMonitor)

    {

        pMonitor->ShowWindow(SW_SHOWMAXIMIZED);

        pMonitor->MoveWindow(&pMonitor->MonRect, TRUE);

    }

}

}

Siji, Merlin 0 Reputation points

2026-02-25T09:10:25.6633333+00:00

Since the code is not properly displayed in above description, explaining it below:

When SC_RESTORE is received:``

For each monitor window:``

Call ShowWindow (SW_SHOWMAXIMIZED)``

Then reposition the window using MoveWindow
Viorel 126.8K Reputation points

2026-02-25T10:25:39.69+00:00

What happens instead of maximization?

By the way, according to the documentation, if( nID == SC_RESTORE ) is not a reliable check.
Jack Dang (WICLOUD CORPORATION) 15,205 Reputation points Microsoft External Staff Moderator

2026-02-25T10:52:26.4833333+00:00

Hi @Siji, Merlin , I need more time to investigate this issue. I will get back to you as soon as possible.
Siji, Merlin 0 Reputation points

2026-02-25T10:53:50.7266667+00:00

What happens instead of maximization?

Instead of maximizing on all monitors, the window only maximizes on some monitors and does not maximize on the other window, even though the same code is executed for each monitor when SC_RESTORE is received:

For each monitor window:

{

Call ShowWindow (SW_SHOWMAXIMIZED)

Then reposition the window using MoveWindow

}

i.e, In these scenarios, if (nID == SC_RESTORE) still behaves correctly for all monitors.
Viorel 126.8K Reputation points

2026-02-25T11:04:41.3666667+00:00

Maybe MoveWindow does not have sense after maximization or has sense before maximization.
David Lowndes 2,750 Reputation points MVP

2026-02-25T12:34:54.5266667+00:00
You don't appear to be masking the wParam (nID) value before comparing it.

(nID & 0xFFF0) == SC_*

2 answers

Your answer

Deleted

This comment has been deleted due to a violation of our Code of Conduct. The comment was manually reported or identified through automated detection before action was taken. Please refer to our Code of Conduct for more information.
Siji, Merlin 0 Reputation points

2026-02-25T09:02:05.7033333+00:00

if (nID == SC_RESTORE)

{

for (int i = 0; i < NoOfMainFrmAlive; ++i) { PvMonitor* pMonitor = (PvMonitor*)m_MainFrameArr.GetAt(i); if (pMonitor) { pMonitor->ShowWindow(SW_SHOWMAXIMIZED); pMonitor->MoveWindow(&pMonitor->MonRect, TRUE); } }

}
Siji, Merlin 0 Reputation points

2026-02-25T09:10:25.6633333+00:00

Since the code is not properly displayed in above description, explaining it below:

When SC_RESTORE is received:``

For each monitor window:``

Call ShowWindow (SW_SHOWMAXIMIZED)``

Then reposition the window using MoveWindow
Viorel 126.8K Reputation points

2026-02-25T10:25:39.69+00:00

What happens instead of maximization?

By the way, according to the documentation, if( nID == SC_RESTORE ) is not a reliable check.
Jack Dang (WICLOUD CORPORATION) 15,205 Reputation points Microsoft External Staff Moderator

2026-02-25T10:52:26.4833333+00:00

Hi @Siji, Merlin , I need more time to investigate this issue. I will get back to you as soon as possible.
Siji, Merlin 0 Reputation points

2026-02-25T10:53:50.7266667+00:00

What happens instead of maximization?

Instead of maximizing on all monitors, the window only maximizes on some monitors and does not maximize on the other window, even though the same code is executed for each monitor when SC_RESTORE is received:

For each monitor window:

{

Call ShowWindow (SW_SHOWMAXIMIZED)

Then reposition the window using MoveWindow

}

i.e, In these scenarios, if (nID == SC_RESTORE) still behaves correctly for all monitors.
Viorel 126.8K Reputation points

2026-02-25T11:04:41.3666667+00:00

Maybe MoveWindow does not have sense after maximization or has sense before maximization.
David Lowndes 2,750 Reputation points MVP

2026-02-25T12:34:54.5266667+00:00

You don't appear to be masking the wParam (nID) value before comparing it.

(nID & 0xFFF0) == SC_*

Answer 1

Hi @Siji, Merlin ,

Thanks for reaching out.

I looked at the behavior you’re seeing with SW_SHOWMAXIMIZED on Windows 11 23H2 in a multi-monitor MFC setup. Specifically:

When you call ShowWindow(SW_SHOWMAXIMIZED) and then immediately MoveWindow, Windows may not always apply the maximized state to all monitors consistently. In Windows 10, this sequence often “just worked,” but Windows 11 is stricter about letting the system handle maximized window positioning.
Your current if (nID == SC_RESTORE) check is also a bit fragile, it’s better to mask the lower bits like (nID & 0xFFF0) == SC_RESTORE to reliably catch restore messages.

I suggest a couple of approaches:

Let the system handle maximization: Call ShowWindow(SW_SHOWMAXIMIZED) for each window and avoid calling MoveWindow afterward. Windows will place the window on the correct monitor.
Reposition before maximizing: If you need precise positioning, call MoveWindow first to set the bounds, then call ShowWindow(SW_SHOWMAXIMIZED), which should ensure the window is maximized with the intended geometry.

Hope this helps! If my answer was helpful - kindly follow the instructions here so others with the same problem can benefit as well.

Michael Le (WICLOUD CORPORATION) 11,085 Reputation points Microsoft External Staff Moderator

2026-03-03T09:05:12.45+00:00

Hello @Siji, Merlin ,

It's been a while since we last heard from you. Hope things are going well.

If you're still interested or have any questions, feel free to reach out whenever it works best for you.

Answer 2

There has been a change in window management behavior in Windows 11, particularly in version 23H2, which may affect how SW_SHOWMAXIMIZED operates in multi-monitor setups. While the specific details of this change are not explicitly documented in the provided context, it is noted that applications may experience different behaviors when restoring from minimized states.

In your case, since replacing SW_SHOWMAXIMIZED with SW_RESTORE resolves the issue, it suggests that the new behavior in Windows 11 23H2 may not handle maximization across multiple monitors as it did in Windows 10. This could be due to changes in how Windows 11 manages window states and monitor configurations.

As a recommended approach, you might consider implementing a conditional check in your OnSysCommand method to determine the current operating system version. If it detects Windows 11 23H2 or later, you could use SW_RESTORE for restoring the window, while continuing to use SW_SHOWMAXIMIZED in other parts of your application where it is necessary. This hybrid approach would maintain compatibility with both Windows 10 and Windows 11 behaviors without requiring extensive changes to your existing codebase.

References:

Resolved issues in Windows 11, version 23H2

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Windows 11 – Different behavior of SW_SHOWMAXIMIZED in multi-monitor MFC application

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