Dear Singular Users,
the Cygwin project has released a new X server for Cygwin. The startup script "startxserver.bat" provided by the package "singular-icons" is therefore out of date.
We will shortly release Singular 3-1-0 which will work with the current Cygwin X server. In the meantime you can correct the current script by deleting the following four lines from the file "/usr/X11R6/bin/startxwin.bat" resp. "c:cygwinusrX11R6binstartxwin.bat":
We thank Jon Turney for reporting the problem and providing the solution.