diff --git a/Sources/Plasma/CoreLib/HeadSpin.cpp b/Sources/Plasma/CoreLib/HeadSpin.cpp
index c9a50e54..356109c4 100644
--- a/Sources/Plasma/CoreLib/HeadSpin.cpp
+++ b/Sources/Plasma/CoreLib/HeadSpin.cpp
@@ -175,23 +175,6 @@ void DebugMsg(const char fmt[], ...)
     }
 }
 
-void ErrorMinimizeAppWindow () 
-{
-#ifdef HS_BUILD_FOR_WIN32
-    // If the application's topmost window is a fullscreen
-    // popup window, minimize it before displaying an error
-    HWND appWindow = GetActiveWindow();
-    if ( ((GetWindowLong(appWindow, GWL_STYLE) & WS_POPUP) != 0) )
-        SetWindowPos(
-            appWindow,
-            HWND_NOTOPMOST,
-            0, 0, // position
-            0, 0, // size
-            SWP_HIDEWINDOW | SWP_NOMOVE | SWP_NOSIZE
-        );
-#endif
-}
-
 ///////////////////////////////////////////////////////////////////
 
 
diff --git a/Sources/Plasma/CoreLib/hsUtils.cpp b/Sources/Plasma/CoreLib/hsUtils.cpp
index 60a37f3f..45e5f0e0 100644
--- a/Sources/Plasma/CoreLib/hsUtils.cpp
+++ b/Sources/Plasma/CoreLib/hsUtils.cpp
@@ -70,9 +70,34 @@ char *hsScalarToStr(float s)
     return hsStrBuf;
 }
 
+class hsMinimizeClientGuard
+{
+#ifdef CLIENT
+    hsWindowHndl fWnd;
+
+public:
+    hsMinimizeClientGuard()
+    {
+#ifdef HS_BUILD_FOR_WIN32
+        fWnd = GetActiveWindow();
+        // If the application's topmost window is fullscreen, minimize it before displaying an error
+        if ((GetWindowLong(fWnd, GWL_STYLE) & WS_POPUP) != 0)
+            ShowWindow(fWnd, SW_MINIMIZE);
+#endif // HS_BUILD_FOR_WIN32
+    }
+
+    ~hsMinimizeClientGuard()
+    {
+#ifdef HS_BUILD_FOR_WIN32
+        ShowWindow(fWnd, SW_RESTORE);
+#endif // HS_BUILD_FOR_WIN32
+    }
+#endif // CLIENT
+};
+
 bool hsMessageBox_SuppressPrompts = false;
 
-int hsMessageBoxWithOwner(void * owner, const char message[], const char caption[], int kind, int icon)
+int hsMessageBoxWithOwner(hsWindowHndl owner, const char message[], const char caption[], int kind, int icon)
 {
     if (hsMessageBox_SuppressPrompts)
         return hsMBoxOk;
@@ -106,10 +131,8 @@ int hsMessageBoxWithOwner(void * owner, const char message[], const char caption
     else
         flags |= MB_ICONERROR;
 
-#ifdef CLIENT
-    ErrorMinimizeAppWindow();
-#endif
-    int ans = MessageBox((HWND)owner, message, caption, flags);
+    hsMinimizeClientGuard guard;
+    int ans = MessageBox(owner, message, caption, flags);
 
     switch (ans)
     {
@@ -126,7 +149,7 @@ int hsMessageBoxWithOwner(void * owner, const char message[], const char caption
 #endif
 }
 
-int hsMessageBoxWithOwner(void * owner, const wchar_t message[], const wchar_t caption[], int kind, int icon)
+int hsMessageBoxWithOwner(hsWindowHndl owner, const wchar_t message[], const wchar_t caption[], int kind, int icon)
 {
     if (hsMessageBox_SuppressPrompts)
         return hsMBoxOk;
@@ -160,10 +183,8 @@ int hsMessageBoxWithOwner(void * owner, const wchar_t message[], const wchar_t c
     else
         flags |= MB_ICONERROR;
     
-#ifdef CLIENT
-    ErrorMinimizeAppWindow();
-#endif
-    int ans = MessageBoxW((HWND)owner, message, caption, flags);
+    hsMinimizeClientGuard guard;
+    int ans = MessageBoxW(owner, message, caption, flags);
     
     switch (ans)
     {
@@ -182,20 +203,12 @@ int hsMessageBoxWithOwner(void * owner, const wchar_t message[], const wchar_t c
 
 int hsMessageBox(const char message[], const char caption[], int kind, int icon)
 {
-#if HS_BUILD_FOR_WIN32
-    return hsMessageBoxWithOwner(nil/*GetActiveWindow()*/,message,caption,kind,icon);
-#else
-    return hsMessageBoxWithOwner(nil,message,caption,kind,icon);
-#endif
+    return hsMessageBoxWithOwner((hsWindowHndl)nil,message,caption,kind,icon);
 }
 
 int hsMessageBox(const wchar_t message[], const wchar_t caption[], int kind, int icon)
 {
-#if HS_BUILD_FOR_WIN32
-    return hsMessageBoxWithOwner(nil/*GetActiveWindow()*/,message,caption,kind,icon);
-#else
-    return hsMessageBoxWithOwner(nil,message,caption,kind,icon);
-#endif
+    return hsMessageBoxWithOwner((hsWindowHndl)nil,message,caption,kind,icon);
 }
 
 inline hsBool hsCompare(float a, float b, float delta)
diff --git a/Sources/Plasma/CoreLib/hsUtils.h b/Sources/Plasma/CoreLib/hsUtils.h
index 0559c4be..8bf36fef 100644
--- a/Sources/Plasma/CoreLib/hsUtils.h
+++ b/Sources/Plasma/CoreLib/hsUtils.h
@@ -126,8 +126,8 @@ enum {          // RETURN VALUES FROM hsMessageBox
 extern bool hsMessageBox_SuppressPrompts;
 int hsMessageBox(const char message[], const char caption[], int kind, int icon=hsMessageBoxIconAsterisk);
 int hsMessageBox(const wchar_t message[], const wchar_t caption[], int kind, int icon=hsMessageBoxIconAsterisk);
-int hsMessageBoxWithOwner(void* owner, const char message[], const char caption[], int kind, int icon=hsMessageBoxIconAsterisk);
-int hsMessageBoxWithOwner(void* owner, const wchar_t message[], const wchar_t caption[], int kind, int icon=hsMessageBoxIconAsterisk);
+int hsMessageBoxWithOwner(hsWindowHndl owner, const char message[], const char caption[], int kind, int icon=hsMessageBoxIconAsterisk);
+int hsMessageBoxWithOwner(hsWindowHndl owner, const wchar_t message[], const wchar_t caption[], int kind, int icon=hsMessageBoxIconAsterisk);
 
 inline hsBool hsCompare(float a, float b, float delta=0.0001);
 
@@ -217,7 +217,6 @@ hsDebugMessageProc hsSetStatusMessageProc(hsDebugMessageProc newProc);
 
 void ErrorEnableGui (bool enabled);
 void ErrorAssert (int line, const char file[], const char fmt[], ...);
-void ErrorMinimizeAppWindow ();
 
 bool DebugIsDebuggerPresent ();
 void DebugBreakIfDebuggerPresent ();