From 6e63704edac355cc8cae62092c0433c608221266 Mon Sep 17 00:00:00 2001
From: "Dustin L. Howett" <dustin@howett.net>
Date: Thu, 18 Dec 2025 19:04:18 -0600
Subject: [PATCH] Try: Pass foreground rights across the handoff and Monarchy
 stacks

---
 src/cascadia/WindowsTerminal/IslandWindow.cpp | 32 ++++++-------------
 src/cascadia/wt/shim.cpp                      | 24 +++++++++++++-
 src/host/srvinit.cpp                          |  5 +++
 3 files changed, 37 insertions(+), 24 deletions(-)

diff --git a/src/cascadia/WindowsTerminal/IslandWindow.cpp b/src/cascadia/WindowsTerminal/IslandWindow.cpp
index e627bd4495..3a592d3a39 100644
--- a/src/cascadia/WindowsTerminal/IslandWindow.cpp
+++ b/src/cascadia/WindowsTerminal/IslandWindow.cpp
@@ -1457,32 +1457,18 @@ void IslandWindow::_globalActivateWindow(const uint32_t dropdownDuration,
     }
     else
     {
-        // Try first to send a message to the current foreground window. If it's not responding, it may
-        // be waiting on us to finish launching. Passing SMTO_NOTIMEOUTIFNOTHUNG means that we get the same
-        // behavior as before--that is, waiting for the message loop--but we've done an early return if
-        // it turns out that it was hung.
-        // SendMessageTimeoutW returns nonzero if it succeeds.
-        if (0 != SendMessageTimeoutW(oldForegroundWindow, WM_NULL, 0, 0, SMTO_NOTIMEOUTIFNOTHUNG | SMTO_BLOCK | SMTO_ABORTIFHUNG, 1000, nullptr))
-        {
-            const auto windowThreadProcessId = GetWindowThreadProcessId(oldForegroundWindow, nullptr);
-            const auto currentThreadId = GetCurrentThreadId();
+        LOG_IF_WIN32_BOOL_FALSE(BringWindowToTop(_window.get()));
+        ShowWindow(_window.get(), SW_SHOW);
 
-            LOG_IF_WIN32_BOOL_FALSE(AttachThreadInput(windowThreadProcessId, currentThreadId, true));
-            // Just in case, add the thread detach as a scope_exit, to make _sure_ we do it.
-            auto detachThread = wil::scope_exit([windowThreadProcessId, currentThreadId]() {
-                LOG_IF_WIN32_BOOL_FALSE(AttachThreadInput(windowThreadProcessId, currentThreadId, false));
-            });
-            LOG_IF_WIN32_BOOL_FALSE(BringWindowToTop(_window.get()));
-            ShowWindow(_window.get(), SW_SHOW);
+        // Activate the window too. This will force us to the virtual desktop this
+        // window is on, if it's on another virtual desktop.
+        LOG_LAST_ERROR_IF_NULL(SetActiveWindow(_window.get()));
 
-            // Activate the window too. This will force us to the virtual desktop this
-            // window is on, if it's on another virtual desktop.
-            LOG_LAST_ERROR_IF_NULL(SetActiveWindow(_window.get()));
-
-            // Throw us on the active monitor.
-            _moveToMonitor(oldForegroundWindow, toMonitor);
-        }
+        // Throw us on the active monitor.
+        _moveToMonitor(oldForegroundWindow, toMonitor);
     }
+
+    SetForegroundWindow(_window.get());
 }
 
 // Method Description:
diff --git a/src/cascadia/wt/shim.cpp b/src/cascadia/wt/shim.cpp
index 0b00fcaf96..23016c57fd 100644
--- a/src/cascadia/wt/shim.cpp
+++ b/src/cascadia/wt/shim.cpp
@@ -6,10 +6,19 @@
 #include <wil/stl.h>
 #include <wil/resource.h>
 #include <wil/win32_helpers.h>
+#include <TraceLoggingProvider.h>
+
+TRACELOGGING_DECLARE_PROVIDER(g_hProvider1);
+TRACELOGGING_DEFINE_PROVIDER(
+    g_hProvider1,
+    "Microsoft.Windows.Terminal.Shim",
+    // tl:{d295502a-ab39-5565-c342-6e6d7659a422}
+    (0xd295502a,0xab39,0x5565,0xc3,0x42,0x6e,0x6d,0x76,0x59,0xa4,0x22));
 
 #pragma warning(suppress : 26461) // we can't change the signature of wWinMain
 int __stdcall wWinMain(HINSTANCE, HINSTANCE, LPWSTR pCmdLine, int)
 {
+    TraceLoggingRegister(g_hProvider1);
     std::filesystem::path module{ wil::GetModuleFileNameW<std::wstring>(nullptr) };
 
     // Cache our name (wt, wtd)
@@ -32,5 +41,18 @@ int __stdcall wWinMain(HINSTANCE, HINSTANCE, LPWSTR pCmdLine, int)
 
     // Go!
     wil::unique_process_information pi;
-    return !CreateProcessW(module.c_str(), cmdline.data(), nullptr, nullptr, FALSE, 0, nullptr, nullptr, &si, &pi);
+    if (!CreateProcessW(module.c_str(), cmdline.data(), nullptr, nullptr, FALSE, CREATE_SUSPENDED, nullptr, nullptr, &si, &pi))
+    {
+        return 1;
+    }
+
+    DWORD lastError = 0;
+    if (!AllowSetForegroundWindow(pi.dwProcessId))
+    {
+        lastError = GetLastError();
+    }
+    TraceLoggingWrite(g_hProvider1, "ShimAllowSetForeground", TraceLoggingWinError(lastError, "lastError"));
+
+    ResumeThread(pi.hThread);
+    return 0;
 }
diff --git a/src/host/srvinit.cpp b/src/host/srvinit.cpp
index cdb49db1bd..883489fea4 100644
--- a/src/host/srvinit.cpp
+++ b/src/host/srvinit.cpp
@@ -544,6 +544,11 @@ try
 
     myStartupInfo.wShowWindow = settings.GetShowWindow();
 
+    {
+        HRESULT hr = CoAllowSetForegroundWindow(handoff.Get(), nullptr);
+        TraceLoggingWrite(g_hConhostV2EventTraceProvider, "PtyHandoffAllowSetForegroundWindow", TraceLoggingHResult(hr));
+    }
+
     wil::unique_handle inPipeOurSide;
     wil::unique_handle outPipeOurSide;
     RETURN_IF_FAILED(handoff->EstablishPtyHandoff(inPipeOurSide.addressof(),