This patch sets an application identifier string under Windows 7, 

The problem is that emacs.exe and emacsclient.exe are separate executables, and so pinning emacsclient.exe to the taskbar clutters the taskbar (see attached before.png; the left icon is a shortcut to emacsclientw, the rightmost is the running emacs instance).

As documented at http://msdn.microsoft.com/en-us/library/dd378459.aspx, this situation can be avoided.by setting an application identifier when starting both processes (after.png).

-- Ben