Re: [PATCH v7 0/2] MR8258: comctl32/treeview: Return from TREEVIEW_LButtonDown when the treeview handle is invalid.

[Zhiyi Zhang (＠zhiyi)]

Zhiyi Zhang (@zhiyi) commented about dlls/comctl32/treeview.c:
>  return SendMessageW(infoPtr->hwndNotify, WM_NOTIFY, hdr->idFrom, (LPARAM)hdr);
>
> }
>
> +static INT
> +TREEVIEW_SendSafeNotify(const TREEVIEW_INFO *infoPtr, UINT code)

It seems better to me to separate the result of the sent notification from the result of IsWindow(). What about something like this?
```
static BOOL TREEVIEW_SendSimpleNotify(const TREEVIEW_INFO *infoPtr, UINT code, LRESULT *result)
{
    NMHDR hdr;
    HWND hwnd;

hwnd = infoPtr->hwnd; /* save hwnd before after TREEVIEW_SendRealNotify(), the window could be already destroyed after sending notifications */
    *result = TREEVIEW_SendRealNotify(infoPtr, code, &hdr);
    return IsWindow(hwnd);
}
```

Then, at places where TREEVIEW_SendSimpleNotify() is used. Check its return value before using the notification result. And if TREEVIEW_SendSimpleNotify() returns FALSE, then return from the message handler immediately.