PHP Autosave - not functioning in Linux version under WSL

I am using WSL as a linux environment under windows, and so Phpstorm has direct access to the file system (not using a network share), I have the linux version installed and running under the 3rd party X Server, VcXsrv, unfortunately, autosave in phpstorm is completely broken, it won't save automatically on switching applications, switching tabs, or even using the autosave after 15s  idle. the only way to have it save the file is to manual Ctrl+S to save the file, or to quit the application.