I just figured this is not an error. I get two window handles because the first one is for the window itself and the second one for the opened file. Like how it works in Microsoft Visual C++ editor. After closing the file, the editor is still open. And that's precisely happening in my case too. I do a ALT F4 and the file gets closed and the XVI32 editor remains open which I need to close explicitly again

I hope my understanding is correct