Prevents some UWP popups from closing due to UWPSpy stealing focus. See https://github.com/m417z/UWPSpy/issues/8.

ignore-focus-loss-fork.wh.cpp

// ==WindhawkMod==
// @id              prevent-uwpspy-focus-steal
// @name            Prevent UWPSpy Focus Steal
// @description     Prevents some UWP popups from closing due to UWPSpy stealing focus
// @version         0.1
// @author          m417z
// @github          https://github.com/m417z
// @twitter         https://x.com/m417z
// @homepage        https://m417z.com/
// @compilerOptions -lcomctl32
// @include         *
// ==/WindhawkMod==

// ==WindhawkModReadme==
/*
# Prevent UWPSpy Focus Steal

Prevents some UWP popups from closing due to UWPSpy stealing focus. See [UWPSpy
Feature Request: Ability to "pause" or
"save"](https://github.com/m417z/UWPSpy/issues/8).
*/
// ==/WindhawkModReadme==

#include <windhawk_utils.h>

// Suppress the messages we want to ignore
// and prevent them from reaching the main windowProc
LRESULT CALLBACK TargetWindowSubclassProc(HWND hWnd,
                                          UINT uMsg,
                                          WPARAM wParam,
                                          LPARAM lParam,
                                          DWORD_PTR dwRefData) {
    switch (uMsg) {
        case WM_NCACTIVATE:  // Non-client area activation (e.g. titlebar)
            if (!wParam) {
                return FALSE;
            }
            break;
    }

    return DefSubclassProc(hWnd, uMsg, wParam, lParam);
}

bool IsTargetWindow(HWND hwnd) {
    WCHAR className[64];
    if (!GetClassName(hwnd, className, ARRAYSIZE(className))) {
        return false;
    }

    return _wcsicmp(className, L"UWPSpy") == 0;
    // return _wcsicmp(className, L"XamlExplorerHostIslandWindow_WASDK") == 0;
}

// ------------------ Dealing with newly created windows ------------------
// Hooks for creating and destroying new windows to ensure that
// new windows created after the mod is initially enabled get subclassed

using PUNICODE_STRING = PVOID;

// https://github.com/sandboxie-plus/Sandboxie/blob/294966c7d6e99cd153ede87ad09aa39ef29e34c3/Sandboxie/core/dll/Win32.c#L25
using NtUserCreateWindowEx_t = HWND(WINAPI*)(DWORD dwExStyle,
                                             PUNICODE_STRING UnsafeClassName,
                                             LPCWSTR VersionedClass,
                                             PUNICODE_STRING UnsafeWindowName,
                                             DWORD dwStyle,
                                             LONG x,
                                             LONG y,
                                             LONG nWidth,
                                             LONG nHeight,
                                             HWND hWndParent,
                                             HMENU hMenu,
                                             HINSTANCE hInstance,
                                             LPVOID lpParam,
                                             DWORD dwShowMode,
                                             DWORD dwUnknown1,
                                             DWORD dwUnknown2,
                                             VOID* qwUnknown3);
NtUserCreateWindowEx_t NtUserCreateWindowEx_Original;
HWND WINAPI NtUserCreateWindowEx_Hook(DWORD dwExStyle,
                                      PUNICODE_STRING UnsafeClassName,
                                      LPCWSTR VersionedClass,
                                      PUNICODE_STRING UnsafeWindowName,
                                      DWORD dwStyle,
                                      LONG x,
                                      LONG y,
                                      LONG nWidth,
                                      LONG nHeight,
                                      HWND hWndParent,
                                      HMENU hMenu,
                                      HINSTANCE hInstance,
                                      LPVOID lpParam,
                                      DWORD dwShowMode,
                                      DWORD dwUnknown1,
                                      DWORD dwUnknown2,
                                      VOID* qwUnknown3) {
    HWND hWnd = NtUserCreateWindowEx_Original(
        dwExStyle, UnsafeClassName, VersionedClass, UnsafeWindowName, dwStyle,
        x, y, nWidth, nHeight, hWndParent, hMenu, hInstance, lpParam,
        dwShowMode, dwUnknown1, dwUnknown2, qwUnknown3);
    if (!hWnd || !IsTargetWindow(hWnd))
        return hWnd;
    WindhawkUtils::SetWindowSubclassFromAnyThread(hWnd,
                                                  TargetWindowSubclassProc, 0);
    Wh_Log(L"New window subclassed: %08X", (DWORD)(UINT_PTR)hWnd);
    return hWnd;
}

// ------------------ Dealing with existing windows ------------------
// We subclass all existing windows when the mod is enabled
// while the program is already running
BOOL CALLBACK InitialEnumTargetWindowsFunc(HWND hWnd, LPARAM lParam) {
    DWORD dwProcessId = 0;
    DWORD dwThreadId = GetWindowThreadProcessId(hWnd, &dwProcessId);
    if (!dwThreadId || dwProcessId != GetCurrentProcessId()) {
        return TRUE;
    }

    if (IsTargetWindow(hWnd)) {
        Wh_Log(L"Existing window subclassed: %08X", (DWORD)(UINT_PTR)hWnd);
        WindhawkUtils::SetWindowSubclassFromAnyThread(
            hWnd, TargetWindowSubclassProc, 0);
    }

    return TRUE;
}

// ------------------ Clean up when mod is disabled ------------------
// Send a message to each windowProc in the process
// If it was subclassed, it will process the message and unsubclass itself
BOOL CALLBACK EnumTargetWindowsUnsubclassFunc(HWND hWnd, LPARAM lParam) {
    DWORD dwProcessId = 0;
    DWORD dwThreadId = GetWindowThreadProcessId(hWnd, &dwProcessId);
    if (!dwThreadId || dwProcessId != GetCurrentProcessId()) {
        return TRUE;
    }

    if (IsTargetWindow(hWnd)) {
        Wh_Log(L"Unsubclass: %08X", (DWORD)(UINT_PTR)hWnd);
        WindhawkUtils::RemoveWindowSubclassFromAnyThread(
            hWnd, TargetWindowSubclassProc);
    }

    return TRUE;
}

BOOL Wh_ModInit() {
    Wh_Log(L">");

    // Ensure subclass will be added to newly created windows
    HMODULE hModule = GetModuleHandle(L"win32u.dll");
    if (!hModule) {
        return FALSE;
    }

    NtUserCreateWindowEx_t pNtUserCreateWindowEx =
        (NtUserCreateWindowEx_t)GetProcAddress(hModule, "NtUserCreateWindowEx");
    if (!pNtUserCreateWindowEx) {
        return FALSE;
    }

    Wh_SetFunctionHook((void*)pNtUserCreateWindowEx,
                       (void*)NtUserCreateWindowEx_Hook,
                       (void**)&NtUserCreateWindowEx_Original);

    return TRUE;
}

void Wh_ModAfterInit() {
    Wh_Log(L">");

    EnumWindows(InitialEnumTargetWindowsFunc, 0);
}

void Wh_ModUninit() {
    Wh_Log(L">");

    EnumWindows(EnumTargetWindowsUnsubclassFunc, 0);
}