[Bug 10327] New: Crash in WINPROC_CallProcAtoW

http://bugs.winehq.org/show_bug.cgi?id=10327

Summary: Crash in WINPROC_CallProcAtoW
           Product: Wine
           Version: CVS/GIT
          Platform: PC
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: wine-user
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

Created an attachment (id=8988)
 --> (http://bugs.winehq.org/attachment.cgi?id=8988)
sample backtrace

since I installed a new cvs build, a program which I use frequently (Action
Request System by Remedy) crashes in WINPROC_CallProcWtoA

I traced the stuff in the debugger and found that we have
in menu.c:1829: 
    menu->hWnd = CreateWindowExW( 0, (LPCWSTR)POPUPMENU_CLASS_ATOM, NULL,
     ....

So classname is an ATOMINT, and in WINPROC_CallProcWtoA it does the following:

class_lenW = strlenW(csW->lpszClass) * sizeof(WCHAR);
              RtlUnicodeToMultiByteSize(&class_lenA, csW->lpszClass,
class_lenW);
and later
              RtlUnicodeToMultiByteN(cls, class_lenA, NULL, csW->lpszClass,
class_lenW);
> From what I read in other functions, there should be something like

if (HIWORD(csA->lpszClass)) around it.

A sample backtrace is attached.