I am running Xserver on cygwin (on top on Windows 7), and then using xterm to remote to linux via ssh -X, and run remote applications there, like konsole, emacs and others.

Initially all works fine, e.g. executing emacs pops up the correctly working window on my Windows 7 box.

But if I try to run the same emacs some time (like an hour) later, I get a linux message Display localhost:10.0 unavailable, simulating -nw and emacs runs in-line.

I have checked and the Xserver seems still up and running ok. Indeed, if I exit out to the original cygwin and reconnect to Linux by ssh -X again, it works just fine.

Would you know what is happening and how can it be fixed? Why is my Xserver connection being dropped?

Thank you very much.