Yes, no problem. However, my XOrg was compiled without Xephyr,=
 so I rebuilt it.
Unfortunately, I've decided to update mesa to latest commit as well, but it
seems that one of recent commits breaks everything (I get an unusable deskt=
op
which looks white and can see gray outlines of KDE taskbar, mouse cursor and
login password box cursor). So, I had to temporarily revert to 13.0.3 mesa.=
 But
there some useful info. First, on 13.0.3 I cannot reproduce fault with
reproducer app. Second, reproducer app looks same under 13.0.3 both on Java=
 7
and Java 8. I found it strange that under Java 7 swing app looks like it sh=
ould
(Metal look & feel) and under Java 8 it looked different (white buttons=
 instead
of default metallic). But it appears that this was just a rendering artefac=
t.

I will try to get back to working mesa commit and reproduce the problem with
Xephyr now.