Comment 28 for bug 1860921

Few notes from my research of this problem:

https://bugzilla.xfce.org/show_bug.cgi?id=16713

> Actually, the problem is the lack of XRender support in the tightvncserver Xserver.

https://sourceforge.net/p/vnc-tight/mailman/message/28243000/

> Unfortunately, TightVNC for Unix/Linux is quite old, it was not updated for years, and I guess it would not be simple to enable Xrender in it.
> So I'd recommend looking at some other VNC-compatible servers for Unix, e.g. TigerVNC or RealVNC's one.

So new vnc server is fastest workaround.
I migrated to TigerVNC but caught https://github.com/TigerVNC/tigervnc/issues/800
Fixed it by adding view-only password with "vncpasswd"
Works fine so far.