diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3810ed60..5033985c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,19 @@ if(TARGET secude_compat)
     set_property(TARGET secude_compat PROPERTY INTERFACE_COMPILE_FEATURES "")
 endif()
 add_subdirectory(port/mfcwx)
+# These libraries open files by paths CrypTool passes in Windows form; the app links mfcwx, which
+# converts them, and the library tests use plain stubs.
+foreach(target cryptool_analyse cryptool_cracklib)
+    target_compile_options(${target} PRIVATE "SHELL:-iquote ${CMAKE_SOURCE_DIR}/port/mfcwx/include"
+                           "SHELL:-include ${CMAKE_SOURCE_DIR}/port/mfcwx/include/mfcwx/pathcompat.h")
+endforeach()
+add_library(mfcwx_path_stubs STATIC port/mfcwx/tests/path_stubs.cpp)
+target_include_directories(mfcwx_path_stubs PRIVATE port/mfcwx/include)
+foreach(test test_analyse test_cracklib)
+    if(TARGET ${test})
+        target_link_libraries(${test} PRIVATE mfcwx_path_stubs)
+    endif()
+endforeach()
 add_subdirectory(port/app)
 
 option(CRYPTOOL_DIALOG_GALLERY "Build the dialog snapshot tool" OFF)
diff --git a/port/app/CMakeLists.txt b/port/app/CMakeLists.txt
index 18b2d002..94fc03af 100644
--- a/port/app/CMakeLists.txt
+++ b/port/app/CMakeLists.txt
@@ -18,7 +18,8 @@ file(GLOB CT_EXTRA_SOURCES CONFIGURE_DEPENDS
     ${REPO_ROOT}/libVolRen/CQuaternion.cpp ${REPO_ROOT}/libVolRen/CVector.cpp ${REPO_ROOT}/libVolRen/Volume.cpp
     ${REPO_ROOT}/libVolRen/VolumeUtilities.cpp ${REPO_ROOT}/ChallengeResponse/*.cpp)
 
-add_executable(CrypTool ${CT_SOURCES} ${CT_EXTRA_SOURCES} ${CMAKE_CURRENT_SOURCE_DIR}/platform.cpp)
+add_executable(CrypTool ${CT_SOURCES} ${CT_EXTRA_SOURCES} ${CMAKE_CURRENT_SOURCE_DIR}/platform.cpp
+                        ${CMAKE_CURRENT_SOURCE_DIR}/miracl_rand.cpp)
 mfcwx_add_rc(CrypTool RC ${CT_SRC}/CrypTool.rc MODULE CrypTool HEADERS ${CT_SRC}/resource.h
              REPLACE "[CRYPTOOL_VERSION_FULL]=CrypTool ${PROJECT_VERSION}" "[CRYPTOOL_VERSION]=${PROJECT_VERSION}")
 
diff --git a/port/app/miracl_rand.cpp b/port/app/miracl_rand.cpp
new file mode 100644
index 00000000..c7fe4326
--- /dev/null
+++ b/port/app/miracl_rand.cpp
@@ -0,0 +1,5 @@
+// Compiled without mfcwx/crtcompat.h: app code sees MIRACL's rand overloads renamed to mfcwx_rand.
+#include "BIG.H"
+
+Big mfcwx_rand(const Big& w) { return rand(w); }
+Big mfcwx_rand(int n, int b) { return rand(n, b); }
diff --git a/port/mfcwx/include/mfcwx/crtcompat.h b/port/mfcwx/include/mfcwx/crtcompat.h
index 17fe75b0..b2b2ac4c 100644
--- a/port/mfcwx/include/mfcwx/crtcompat.h
+++ b/port/mfcwx/include/mfcwx/crtcompat.h
@@ -387,8 +387,20 @@ int _findclose(intptr_t handle);
 #define _findfirsti64 _findfirst
 #define _findnexti64 _findnext
 
+/* rand() of the Microsoft C runtime (per-thread LCG, RAND_MAX 0x7fff); CrypTool sizes buffers for it. */
+int mfcwx_rand(void);
+void mfcwx_srand(unsigned int seed);
+#undef RAND_MAX
+#define RAND_MAX 0x7fff
+#define rand mfcwx_rand
+#define srand mfcwx_srand
+
 #endif /* _MFCWX_CRTCOMPAT */
 
 #ifdef __cplusplus
 }
+namespace std {
+using ::mfcwx_rand;
+using ::mfcwx_srand;
+}
 #endif
diff --git a/port/mfcwx/include/mfcwx/pathcompat.h b/port/mfcwx/include/mfcwx/pathcompat.h
new file mode 100644
index 00000000..5422a201
--- /dev/null
+++ b/port/mfcwx/include/mfcwx/pathcompat.h
@@ -0,0 +1,17 @@
+#pragma once
+
+// Force-included into third-party libraries that open files by paths coming from CrypTool,
+// which are in Windows form ("\dir\file").
+
+#include <stdio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+FILE* mfcwx_fopen(const char* name, const char* mode);
+#ifdef __cplusplus
+}
+#include "mfcwx/fstreamcompat.h"
+#endif
+
+#define fopen mfcwx_fopen
diff --git a/port/mfcwx/src/crt.cpp b/port/mfcwx/src/crt.cpp
index e9353cd5..5adc1ddd 100644
--- a/port/mfcwx/src/crt.cpp
+++ b/port/mfcwx/src/crt.cpp
@@ -848,3 +848,16 @@ intptr_t _spawnl(int mode, const char* cmdname, const char* arg0, ...) {
     CloseHandle(pi.hProcess);
     return 0;
 }
+
+namespace {
+
+thread_local unsigned int g_randSeed = 1;
+
+} // namespace
+
+extern "C" int mfcwx_rand(void) {
+    g_randSeed = g_randSeed * 214013u + 2531011u;
+    return static_cast<int>((g_randSeed >> 16) & 0x7fff);
+}
+
+extern "C" void mfcwx_srand(unsigned int seed) { g_randSeed = seed; }
diff --git a/port/mfcwx/src/snapshot.cpp b/port/mfcwx/src/snapshot.cpp
index 88656884..68559456 100644
--- a/port/mfcwx/src/snapshot.cpp
+++ b/port/mfcwx/src/snapshot.cpp
@@ -7,6 +7,9 @@
 #include <wx/toplevel.h>
 
 #include <cstdlib>
+#include <fstream>
+#include <sstream>
+#include <vector>
 
 namespace mfcwx {
 
@@ -78,9 +81,109 @@ class SnapshotTimer : public wxTimer {
     int m_round = 0;
 };
 
+std::string SafeName(const wxString& title) {
+    std::string name;
+    for (wxUniChar c : title)
+        name += (c.IsAscii() && isalnum(static_cast<int>(c.GetValue()))) ? static_cast<char>(c.GetValue()) : '_';
+    return name.substr(0, 40);
+}
+
+wxWindow* ActiveDialog() {
+    wxWindow* found = nullptr;
+    for (wxWindow* w : wxTopLevelWindows) {
+        auto* d = wxDynamicCast(w, wxDialog);
+        if (d && d->IsShown())
+            found = d;
+    }
+    return found;
+}
+
+// Development aid: MFCWX_AUTOMATION=file runs one step per line on a timer, for UI tests:
+//   command <id>        WM_COMMAND to the main window
+//   button <id>         WM_COMMAND (BN_CLICKED) to the topmost dialog
+//   text <id> <text>    sets the text of a control of the topmost dialog
+//   wait <ms>
+//   snapshot <label>    PNGs of all shown top-level windows into MFCWX_SNAPSHOT_DIR (or .)
+//   quit
+class AutomationTimer : public wxTimer {
+public:
+    AutomationTimer(std::vector<std::string> steps, std::string dir) : m_steps(std::move(steps)), m_dir(std::move(dir)) {}
+
+    void Notify() override {
+        if (m_waitUntil != 0 && wxGetLocalTimeMillis() < m_waitUntil)
+            return;
+        m_waitUntil = 0;
+        if (m_next >= m_steps.size()) {
+            fprintf(stderr, "mfcwx automation: done\n");
+            fflush(stderr);
+            _exit(0);
+        }
+        std::string line = m_steps[m_next++];
+        std::istringstream in(line);
+        std::string op;
+        in >> op;
+        fprintf(stderr, "mfcwx automation: %s\n", line.c_str());
+        if (op == "command" || op == "button") {
+            int id = 0;
+            in >> id;
+            CWnd* target = op == "command" ? AfxGetMainWnd() : WrapperFor(ActiveDialog());
+            if (target && target->m_hWnd)
+                target->PostMessage(WM_COMMAND, MAKEWPARAM(id, BN_CLICKED), 0);
+            else
+                fprintf(stderr, "mfcwx automation: no target window\n");
+        } else if (op == "text") {
+            int id = 0;
+            in >> id;
+            std::string text;
+            std::getline(in, text);
+            if (!text.empty() && text[0] == ' ')
+                text.erase(0, 1);
+            CWnd* dlg = WrapperFor(ActiveDialog());
+            if (dlg && dlg->m_hWnd)
+                ::SetDlgItemText(dlg->m_hWnd, id, text.c_str());
+        } else if (op == "wait") {
+            long ms = 0;
+            in >> ms;
+            m_waitUntil = wxGetLocalTimeMillis() + ms;
+        } else if (op == "snapshot") {
+            std::string label;
+            in >> label;
+            int index = 0;
+            for (wxWindow* w : wxTopLevelWindows) {
+                if (!w->IsShown())
+                    continue;
+                char path[1024];
+                snprintf(path, sizeof path, "%s/%s_%d_%s.png", m_dir.c_str(), label.c_str(), index++,
+                         SafeName(w->GetLabel()).c_str());
+                bool ok = SnapshotWxWindow(w, path);
+                fprintf(stderr, "mfcwx snapshot %s %s\n", ok ? "saved" : "FAILED", path);
+            }
+        } else if (op == "quit") {
+            m_next = m_steps.size();
+        }
+    }
+
+private:
+    std::vector<std::string> m_steps;
+    std::string m_dir;
+    size_t m_next = 0;
+    wxLongLong m_waitUntil = 0;
+};
+
 } // namespace
 
 void StartSnapshotTimerFromEnvironment() {
+    if (const char* script = getenv("MFCWX_AUTOMATION")) {
+        std::ifstream f(script);
+        std::vector<std::string> steps;
+        for (std::string line; std::getline(f, line);)
+            if (!line.empty() && line[0] != '#')
+                steps.push_back(line);
+        const char* outDir = getenv("MFCWX_SNAPSHOT_DIR");
+        static AutomationTimer automation(steps, outDir && *outDir ? outDir : ".");
+        automation.Start(200);
+        return;
+    }
     const char* dir = getenv("MFCWX_SNAPSHOT_DIR");
     if (!dir || !*dir)
         return;
diff --git a/port/mfcwx/src/wnd.cpp b/port/mfcwx/src/wnd.cpp
index cbaf3156..026d4b46 100644
--- a/port/mfcwx/src/wnd.cpp
+++ b/port/mfcwx/src/wnd.cpp
@@ -718,7 +718,10 @@ const CWnd wndNoTopMost;
 CWnd::CWnd() : m_hWnd(nullptr) {}
 
 CWnd::~CWnd() {
-    if (m_hWnd && IsMainThread()) {
+    if (!m_hWnd)
+        return;
+    // Wrappers destroyed on worker threads (dialogs run from AfxBeginThread) must detach too.
+    OnMain([this] {
         wxWindow* w = GetWx();
         WindowState* st = GetState(w);
         if (st && st->permanent == this) {
@@ -730,7 +733,7 @@ CWnd::~CWnd() {
             }
         }
         m_hWnd = nullptr;
-    }
+    });
 }
 
 CWnd* CWnd::FromWx(wxWindow* window) { return WrapperFor(window); }
@@ -1455,7 +1458,7 @@ CWnd* CWnd::SetActiveWindow() { return FromHandle(::SetActiveWindow(m_hWnd)); }
 CWnd* CWnd::GetForegroundWindow() { return FromHandle(::GetForegroundWindow()); }
 BOOL CWnd::SetForegroundWindow() { return ::SetForegroundWindow(m_hWnd); }
 CWnd* CWnd::GetFocus() { return FromHandle(::GetFocus()); }
-CWnd* CWnd::SetFocus() { return FromHandle(::SetFocus(m_hWnd)); }
+CWnd* CWnd::SetFocus() { return FromHandle(::SetFocus(GetSafeHwnd())); }
 CWnd* CWnd::GetDesktopWindow() { return nullptr; }
 CWnd* CWnd::GetCapture() { return FromHandle(::GetCapture()); }
 CWnd* CWnd::SetCapture() { return FromHandle(::SetCapture(m_hWnd)); }
diff --git a/port/mfcwx/tests/path_stubs.cpp b/port/mfcwx/tests/path_stubs.cpp
new file mode 100644
index 00000000..1ef9e00e
--- /dev/null
+++ b/port/mfcwx/tests/path_stubs.cpp
@@ -0,0 +1,12 @@
+#include <cstdio>
+#include <string>
+
+#include "mfcwx/codepage.h"
+
+extern "C" FILE* mfcwx_fopen(const char* name, const char* mode) { return std::fopen(name, mode); }
+
+namespace mfcwx {
+
+std::string NativePath(const char* path) { return path ? path : ""; }
+
+} // namespace mfcwx