Start: Better way to determine the monitor on which the Start menu will open

ExplorerPatcher/StartMenu.c

@@ -66,29 +66,6 @@ void OpenStartOnMonitor(HMONITOR monitor)
     }
 }
 
-typedef struct _MonitorOverrideData
-{
-    DWORD cbIndex;
-    DWORD dwIndex;
-    HMONITOR hMonitor;
-} MonitorOverrideData;
-
-BOOL ExtractMonitorByIndex(HMONITOR hMonitor, HDC hDC, LPRECT lpRect, MonitorOverrideData* mod)
-{
-    POINT pt; pt.x = 0; pt.y = 0;
-    if (MonitorFromPoint(pt, MONITOR_DEFAULTTONULL) == hMonitor)
-    {
-        return TRUE;
-    }
-    if (mod->cbIndex == mod->dwIndex)
-    {
-        mod->hMonitor = hMonitor;
-        return FALSE;
-    }
-    mod->cbIndex++;
-    return TRUE;
-}
-
 LRESULT CALLBACK OpenStartOnCurentMonitorThreadHook(
     int code,
     WPARAM wParam,

ExplorerPatcher/dllmain.c

@@ -10861,6 +10861,15 @@ void StartMenu_LoadSettings(BOOL bRestartIfChanged)
             &StartMenu_ShowAllApps,
             &dwSize
         );
+        dwSize = sizeof(DWORD);
+        RegQueryValueExW(
+            hKey,
+            TEXT("MonitorOverride"),
+            0,
+            NULL,
+            &bMonitorOverride,
+            &dwSize
+        );
         RegCloseKey(hKey);
     }
     RegCreateKeyExW(
@@ -11274,10 +11283,36 @@ int Start_SetWindowRgn(HWND hWnd, HRGN hRgn, BOOL bRedraw)
             HWND hWndTaskbar = NULL;
             if (TaskbarAl)
             {
+                HMONITOR hMonitorOfStartMenu = NULL;
+                if (bMonitorOverride == 1 || !bMonitorOverride) {
+                    POINT pt;
+                    if (!bMonitorOverride) GetCursorPos(&pt);
+                    else {
+                        pt.x = 0; pt.y = 0;
+                    }
+                    hMonitorOfStartMenu = MonitorFromPoint(pt, MONITOR_DEFAULTTOPRIMARY);
+                }
+                else {
+                    MonitorOverrideData mod;
+                    mod.cbIndex = 2;
+                    mod.dwIndex = bMonitorOverride;
+                    mod.hMonitor = NULL;
+                    EnumDisplayMonitors(NULL, NULL, ExtractMonitorByIndex, &mod);
+                    if (mod.hMonitor == NULL)
+                    {
+                        POINT pt; pt.x = 0; pt.y = 0;
+                        hMonitorOfStartMenu = MonitorFromPoint(pt, MONITOR_DEFAULTTOPRIMARY);
+                    }
+                    else
+                    {
+                        hMonitorOfStartMenu = mod.hMonitor;
+                    }
+                }
+
                 HWND hWndTemp = NULL;
 
                 HWND hShellTray_Wnd = FindWindowExW(NULL, NULL, L"Shell_TrayWnd", NULL);
-                if (hShellTray_Wnd && !hWndTaskbar && MonitorFromWindow(hWnd, MONITOR_DEFAULTTOPRIMARY) == MonitorFromWindow(hShellTray_Wnd, MONITOR_DEFAULTTOPRIMARY) && dwOldTaskbarAl)
+                if (hShellTray_Wnd && !hWndTaskbar && hMonitorOfStartMenu == MonitorFromWindow(hShellTray_Wnd, MONITOR_DEFAULTTOPRIMARY) && dwOldTaskbarAl)
                 {
                     hWndTaskbar = hShellTray_Wnd;
                 }
@@ -11292,7 +11327,7 @@ int Start_SetWindowRgn(HWND hWnd, HRGN hRgn, BOOL bRedraw)
                             L"Shell_SecondaryTrayWnd",
                             NULL
                         );
-                        if (hWndTemp && !hWndTaskbar && MonitorFromWindow(hWnd, MONITOR_DEFAULTTOPRIMARY) == MonitorFromWindow(hWndTemp, MONITOR_DEFAULTTOPRIMARY) && dwMMOldTaskbarAl)
+                        if (hWndTemp && !hWndTaskbar && hMonitorOfStartMenu == MonitorFromWindow(hWndTemp, MONITOR_DEFAULTTOPRIMARY) && dwMMOldTaskbarAl)
                         {
                             hWndTaskbar = hWndTemp;
                             break;

ExplorerPatcher/utility.c

@@ -1625,3 +1625,19 @@ void SpotlightHelper(DWORD dwOp, HWND hWnd, HMENU hMenu, LPPOINT pPt)
         CoTaskMemFree(pidl);
     }
 }
+
+BOOL ExtractMonitorByIndex(HMONITOR hMonitor, HDC hDC, LPRECT lpRect, MonitorOverrideData* mod)
+{
+    POINT pt; pt.x = 0; pt.y = 0;
+    if (MonitorFromPoint(pt, MONITOR_DEFAULTTONULL) == hMonitor)
+    {
+        return TRUE;
+    }
+    if (mod->cbIndex == mod->dwIndex)
+    {
+        mod->hMonitor = hMonitor;
+        return FALSE;
+    }
+    mod->cbIndex++;
+    return TRUE;
+}

ExplorerPatcher/utility.h

@@ -584,4 +584,13 @@ BOOL DoesOSBuildSupportSpotlight();
 BOOL IsSpotlightEnabled();
 
 void SpotlightHelper(DWORD dwOp, HWND hWnd, HMENU hMenu, LPPOINT pPt);
+
+typedef struct _MonitorOverrideData
+{
+    DWORD cbIndex;
+    DWORD dwIndex;
+    HMONITOR hMonitor;
+} MonitorOverrideData;
+
+BOOL ExtractMonitorByIndex(HMONITOR hMonitor, HDC hDC, LPRECT lpRect, MonitorOverrideData* mod);
 #endif