App freezing on Linux

[Bryan Buchanan]

I have a customer testing an FX app and more often than not, if the app is
left open for a while (20 minutes or so), either the mouse ceases to work,
or if it does work, when you click a field, or do something that should
re-paint the window, the whole FX window goes totally grey and the app
"disappears".

I've tried starting with "-Dprism.verbose=true -Dprism.order=sw" and
without these options, and it seems to make no difference.

The system is Xubuntu 14.0.43,  kernel 3.13.0-71 running on a Gigabyte
Brix, and Java 64 bit build 1.8.0_60-b27. I don't have this hardware in my
office, but have run up a system with the same OS, kernel and Java, and
cannot re-produce the problem.

Are the any other command line switches, or debug flags that I can set to
try and get a handle on why this is happening ?

(Hope this is the right list for issues like this).