user32: Ignore low instance word in find_class.

dlls/user32/class.c

@@ -299,7 +299,7 @@ static void CLASS_FreeClass( CLASS *classPtr )
 static CLASS *find_class( HINSTANCE module, const WCHAR *name )
 {
     ATOM atom = get_int_atom_value( name );
-    UINT_PTR instance = (UINT_PTR)module;
+    UINT_PTR instance = (UINT_PTR)module & ~0xffff;
     CLASS *class;
 
     USER_Lock();
@@ -313,7 +313,7 @@ static CLASS *find_class( HINSTANCE module, const WCHAR *name )
         {
             if (wcsicmp( class->name, name )) continue;
         }
-        if (!class->local || class->instance == instance)
+        if (!class->local || (class->instance & ~0xffff) == instance)
         {
             TRACE("%s %Ix -> %p\n", debugstr_w(name), instance, class);
             return class;

dlls/user32/tests/class.c

@@ -90,12 +90,14 @@ static void ClassTest(HINSTANCE hInstance, BOOL global)
     WNDCLASSW cls, wc;
     static const WCHAR className[] = {'T','e','s','t','C','l','a','s','s',0};
     static const WCHAR winName[]   = {'W','i','n','C','l','a','s','s','T','e','s','t',0};
+    WNDCLASSW info;
     ATOM test_atom;
     HWND hTestWnd;
     LONG i;
     WCHAR str[20];
     ATOM classatom;
     HINSTANCE hInstance2;
+    BOOL ret;
 
     cls.style         = CS_HREDRAW | CS_VREDRAW | (global?CS_GLOBALCLASS:0);
     cls.lpfnWndProc   = ClassTest_WndProc;
@@ -136,6 +138,9 @@ static void ClassTest(HINSTANCE hInstance, BOOL global)
 
     DestroyWindow(hTestWnd);
 
+    ret = GetClassInfoW(hInstance2, className, &info);
+    ok(ret, "GetClassInfoW failed: %u\n", GetLastError());
+
     hTestWnd = CreateWindowW (className, winName,
        WS_OVERLAPPEDWINDOW + WS_HSCROLL + WS_VSCROLL,
        CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, 0,