Zhiyi Zhang (@zhiyi) commented about dlls/uxtheme/msstyles.c:
start = pszClassList; while((end = wcschr(start, ';'))) { len = end-start;
lstrcpynW(szClassName, start, min(len+1, ARRAY_SIZE(szClassName)));
lstrcpynW(buf, start, min(len+1, ARRAY_SIZE(buf))); start = end+1;
cls = MSSTYLES_FindClass(tfActiveTheme, pszAppName, szClassName);
parse_app_class_name(buf, szAppName, szClassName);
if (szAppName[0])
{
/* If the application class is already set then fail */
Please keep the tests for this case.