I have a strange problem on my notebook running Ubuntu 18.04.2. Every time I open the fifth application window the xserver crashes, i.e. the screen freezes, all applications are terminated, and I see the login screen again. With up to four windows of a kind everything is fine. This behavior is independent of the type of application: it happens with five browser windows as well as with five terminal windows. I tried changing the graphics driver from nvidia-driver-390 to nouveau and even to Intel but without success.
I looked at the Xorg logs but did not find any errors in there. But as I am fairly new to Linux, can someone please tell me where I can find additional information about why the xserver crashes?
