Hello,
I have installed CentOS 7.4.1708 with KDE 4.14.8 and I don't see the option "Window Behavior - Moving - Display content in moving windows" which was previously available in CentOS 5/6 versions. Is this feature available on the new version? It is important as we have very dense display windows and moving them with contents is very slow and blocky.

Thanks in advance!

So you want to disable showing the content of the window while moving or resizing the window?

I suspect that option was removed in recent versions because with compositing it shouldn't affect performance as much because of how it separates the rendering of a window's contents from the displaying of the windows on the screen.

That is moving a window around the screen shouldn't have any notable affect on performance since that doesn't require redrawing the window. Resizing a window could still perform poorly for dense windows, and so for that there should be a Resize Window effect in System Settings -> Desktop Effects -> All Effects -> Window Management that you can enable which will delay the redraw of the window until the resize is complete, instead scaling a snapshot of the window while you resize it.