If you have communication problems with ZigBee devices and some instability or freezes with Z-wave devices, then disable Z-wave global polling. By disabling polling mechanism on my system for a few days in a row, I have no problems, and everything works as expected.  Looks like global polling causes delays not only on device communication but also on UI performances (sometimes just to refresh the browser page takes over half a minute) Please login or register to see this spoiler.   On