XnView - strange problem

I am using XnView for a long time, also for Windows and Mac. Now, I needed for Ubuntu. I have install it, very easy, but, it have a very ugly-strange bug. It seems that all the background of images is transparent, or, the black color is transparent in every picture. I have searched in the Preferences, maybe it is something to set... But, I didn't find nothing abnormal. All seems perfect, only that all my pictures, also the text from the menubar, or from the folder tree is transparent. I will attach some screenshots to be more explicit.

First is my desktop.

Second is with XnView opened and the desktop it is visible.

And on 3rd I have changed the desktop to black, and every picture seems normal, but, it is also the same, problem.

Anybody have any idea what cause this? How to repair it?

Thank you.

Try it with desktop effects disabled.

Yeap, it works now. But, I must change my workflow from now on... :(

I can't keep neither the multi-desktops.

There might be a workaround to get it going with desktop effects. You might ask on their forums. I downloaded it, but I can't determine what language/toolkit it uses to know what workaround to suggest.