Propagate foreground through the stack instead of using tricks

src/cascadia/WindowsTerminal/IslandWindow.cpp

@@ -1457,31 +1457,23 @@ 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);
-        }
+    if (!SetForegroundWindow(_window.get()))
+    {
+        TraceLoggingWrite(g_hWindowsTerminalProvider,
+                          "ActivateSetForegroundWindowFailed",
+                          //TraceLoggingUInt64(static_cast<const unsigned long long>(_window.get()), "hwnd"),
+                          TraceLoggingWinError(GetLastError(), "error"));
     }
 }
 

src/cascadia/WindowsTerminal/WindowEmperor.cpp

@@ -180,7 +180,14 @@ static wil::unique_mutex acquireMutexOrAttemptHandoff(const wchar_t* className,
             DWORD processId = 0;
             if (GetWindowThreadProcessId(hwnd, &processId) && processId)
             {
-                AllowSetForegroundWindow(processId);
+                if (!AllowSetForegroundWindow(processId))
+                {
+                    TraceLoggingWrite(g_hWindowsTerminalProvider,
+                                      "EmperorAllowSetForegroundWindowFailed",
+                                      //TraceLoggingUInt64(static_cast<const unsigned long long>(hwnd), "hwnd"),
+                                      TraceLoggingPid(processId),
+                                      TraceLoggingWinError(GetLastError(), "error"));
+                }
             }
 
             if (SendMessageTimeoutW(hwnd, WM_COPYDATA, 0, reinterpret_cast<LPARAM>(&cds), SMTO_ABORTIFHUNG | SMTO_ERRORONEXIT, 5000, nullptr))

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_hShimProvider);
+TRACELOGGING_DEFINE_PROVIDER(
+    g_hShimProvider,
+    "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_hShimProvider);
     std::filesystem::path module{ wil::GetModuleFileNameW<std::wstring>(nullptr) };
 
     // Cache our name (wt, wtd)
@@ -32,5 +41,19 @@ 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;
+    }
+
+    if (!AllowSetForegroundWindow(pi.dwProcessId))
+    {
+        TraceLoggingWrite(g_hShimProvider,
+                          "ShimAllowSetForegroundWindowFailed",
+                          TraceLoggingPid(pi.dwProcessId, "processId"),
+                          TraceLoggingWinError(GetLastError(), "error"));
+    }
+
+    ResumeThread(pi.hThread);
+    return 0;
 }

src/host/exe/Host.EXE.vcxproj

@@ -88,6 +88,7 @@
     <Link>
       <AllowIsolation>true</AllowIsolation>
       <AdditionalDependencies>winmm.lib;imm32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <DelayLoadDLLs>ext-ms-win-com-ole32-l1.dll</DelayLoadDLLs>
       <DelayLoadDLLs>icu.dll;%(DelayLoadDLLs)</DelayLoadDLLs>
     </Link>
   </ItemDefinitionGroup>

src/host/srvinit.cpp

@@ -544,6 +544,12 @@ try
 
     myStartupInfo.wShowWindow = settings.GetShowWindow();
 
+    if (IsApiSetImplemented("ext-ms-win-com-ole32-l1-1-1"))
+    {
+        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(),