At my company we have a Java UI with two separate windows. From the main window a second one is opened on a different monitor. X is configured to have separate display ids for each monitor (zaphodhead). This configuration worked quiet well for a couple of years on SLES11 machines with different NVidia cards and Java versions. With the same NVidia cards and the same Java version (but a newer X server version) it doesn't work on CentOS or Fedora. The fonts on the second window seem to be transparent.
We tested different Java versions, Intel and NVidia drivers and Window Manager.
I have written a little Java demo UI which reproduces the problem. Please take a look at the following repository where i placed the code, some screenshots and the configurations we tested.
https://github.com/f4n/ZaphodHeadsDemoUI
Do you have any ideas what we are missing in our xorg.conf? Or is the zaphodhead mode discontinued? Do you think it's a Java problem even if the same Java version is working on an older X?
With xrandr/xinerama the UI works fine but we have the problem to place different applications on the correct monitor. I know about the -geometry option but not all applications support this (like firefox), wmctrl works for firefox but not with xeyes (for example). Is there a common or better way?
I postet this on the X.org mailing list too but no one had an idea: https://lists.x.org/archives/xorg/2017-April/058711.html
