Recently this icon started to appear in my Windows 7 x64 task switcher (the one that is currenly selected in the screen shot below). It has no title and there is no visible window associated with this task, i.e. I cannot bring it into the foreground and I cannot close it using Alt-F4.
I have not been able to identify the process that creates it. It is always there, even immediately after logging on. I sifted through all the processes using ProcessExplorer. I killed every process that is non-essential, but the icon was still showing up. I looked at everything in Autoruns, but did not find a suspicious entry.
Can someone recommend a tool or technique for how to find the process that creates this icon?