Xfce4 artifact

After start of FRD some artifact on my screen appear. It looks like the picture which was on the same place when the FRD started. It appear only when FRD starts and with every its start. I have to restart xfwm4 and it is very annoying.

How can I solve it?

Thanks

It's out of scope of FRD's source code. Problem is related somewhere to OS/graphics drivers/Java JRE...

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I've reinstalled system, but it doesn't help.

So I tried to disable tray icon in frd and it seems that it helped.