Restore the Windows 11 taskbar transparency and custom start button.

Src/StartMenu/StartMenu.cpp

@@ -104,6 +104,8 @@ static bool HookStartMenu( THookMode mode, HWND &menu )
 		int err=GetLastError();
 		DllLogToFile(STARTUP_LOG,L"StartMenu: hook failed: 0x%08X",err);
 	}
+	else
+		ConnectWin11Taskbar(process);
 	PostMessage(g_TaskBar,WM_NULL,0,0); // make sure there is one message in the queue
 
 	return true;

Src/StartMenu/StartMenuDLL/StartMenuDLL.cpp

@@ -14,6 +14,7 @@
 #include "ResourceHelper.h"
 #include "LogManager.h"
 #include "TouchHelper.h"
+#include "Win11Taskbar.h"
 #include "IatHookHelper.h"
 #include "dllmain.h"
 #include <uxtheme.h>
@@ -1296,6 +1297,9 @@ static void UpdateStartButtonPosition(const TaskbarInfo* taskBar, const WINDOWPO
 			buttonFlags |= SWP_NOZORDER;
 	}
 
+	// rcTask is nudged by a pixel below for the classic Win32 button. Keep the real bar rect.
+	const RECT rcTaskRaw = rcTask;
+
 	if (!IsStartButtonSmallIcons(taskBar->taskbarId))
 	{
 		bool bClassic;
@@ -1343,6 +1347,23 @@ static void UpdateStartButtonPosition(const TaskbarInfo* taskBar, const WINDOWPO
 		else
 			y = rcTask.bottom - taskBar->startButtonSize.cy;
 
+		// Win11 start hit target, measured at 96 DPI on a 48px bar: a 40px square,
+		// 4px from the top and bottom and 12px from the screen edge. The classic
+		// 1px drop and the left-edge pin leave a custom image low and left of it.
+		if (IsWin11() && GetStartButtonType() == START_BUTTON_CUSTOM && !GetSettingBool(L"StartButtonAlign") && !g_epTaskbar)
+		{
+			const int margin = ScaleForDpi(taskBar->taskBar, 4);
+			const int lead = ScaleForDpi(taskBar->taskBar, 12);
+			int slot = (rcTaskRaw.bottom - rcTaskRaw.top) - margin * 2;
+			if (slot < 1)
+				slot = rcTaskRaw.bottom - rcTaskRaw.top;
+			if (GetWindowLongPtr(taskBar->rebar, GWL_EXSTYLE) & WS_EX_LAYOUTRTL)
+				x = rcTaskRaw.right - lead - slot + (slot - taskBar->startButtonSize.cx) / 2;
+			else
+				x = rcTaskRaw.left + lead + (slot - taskBar->startButtonSize.cx) / 2;
+			y = rcTaskRaw.top + margin + (slot - taskBar->startButtonSize.cy) / 2;
+		}
+
 		// Start button on Win11 is a bit shifted to the right
 		// We will shift our Aero button to cover original button
 		if (IsWin11() && (x == info.rcMonitor.left) && (GetStartButtonType() == START_BUTTON_AERO) && !g_epTaskbar)
@@ -1628,7 +1649,8 @@ static void ComputeTaskbarColors( int *data )
 {
 	bool bDefLook;
 	int look=GetSettingInt(L"TaskbarLook",bDefLook);
-	if (GetWinVersion()<WIN_VER_WIN10 || !IsAppThemed() || look==TASKBAR_AEROGLASS || (look==TASKBAR_TRANSPARENT && g_TaskbarTexture))
+	// On Windows 11 a disabled accent is a black plate behind the XAML bar. Keep the accent alive there.
+	if (GetWinVersion()<WIN_VER_WIN10 || !IsAppThemed() || look==TASKBAR_AEROGLASS || (look==TASKBAR_TRANSPARENT && g_TaskbarTexture && !IsWin11()))
 	{
 		memset(data,0,16);
 	}
@@ -2643,6 +2665,8 @@ void UpdateTaskBars( TUpdateTaskbar update )
 		InvalidateRect(taskBar.taskBar,NULL,TRUE);
 		PostMessage(taskBar.taskBar,WM_THEMECHANGED,0,0);
 	}
+	if (IsWin11())
+		ApplyWin11Taskbar();
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -3227,6 +3251,8 @@ if (!g_bTrimHooks)
 
 	UpdateTaskBars(TASKBAR_RECREATE_BUTTONS);
 	UpdateTaskBars(TASKBAR_UPDATE_TEXTURE);
+	if (IsWin11())
+		StartWin11TaskbarConnect();
 }
 
 static void RecreateStartButton( size_t taskbarId )

Src/StartMenu/StartMenuDLL/StartMenuDLL.h

@@ -18,6 +18,9 @@ STARTMENUAPI HWND FindTaskBar( DWORD process );
 // WH_GETMESSAGE hook for the explorer's GUI thread. The start menu exe uses this hook to inject code into the explorer process
 STARTMENUAPI LRESULT CALLBACK HookInject( int code, WPARAM wParam, LPARAM lParam );
 
+// Ask Explorer's XAML taskbar to load our tap. Called from StartMenu.exe. No-op on older Windows.
+STARTMENUAPI void ConnectWin11Taskbar( DWORD explorerPid );
+
 // Toggle the start menu. bKeyboard - set to true to show the keyboard cues
 STARTMENUAPI HWND ToggleStartMenu( int taskbarId, bool bKeyboard );
 

Src/StartMenu/StartMenuDLL/StartMenuDLL.vcxproj

@@ -89,6 +89,7 @@
       <PrecompiledHeader>Create</PrecompiledHeader>
     </ClCompile>
     <ClCompile Include="TouchHelper.cpp" />
+    <ClCompile Include="Win11Taskbar.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Accessibility.h" />
@@ -110,6 +111,7 @@
     <ClInclude Include="stdafx.h" />
     <ClInclude Include="targetver.h" />
     <ClInclude Include="TouchHelper.h" />
+    <ClInclude Include="Win11Taskbar.h" />
   </ItemGroup>
   <ItemGroup>
     <Image Include="..\..\Setup\OpenShell.ico" />

Src/StartMenu/StartMenuDLL/StartMenuDLL.vcxproj.filters

@@ -72,6 +72,9 @@
     <ClCompile Include="TouchHelper.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="Win11Taskbar.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="Accessibility.h">
@@ -125,6 +128,9 @@
     <ClInclude Include="targetver.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="Win11Taskbar.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
     <ClInclude Include="TouchHelper.h">
       <Filter>Header Files</Filter>
     </ClInclude>