Is there some kind of ZBuffer for the presentation layer in WinRT? The performance issue I have with WPF is more to do that simple fact that, there is only one Dispatcher thread for the main GUI, and there is no ZBuffer at all. It is as if you are trying to draw everything without ZBuffer on single thread, that's terrible. I want to draw in the background in the ZBuffer, using different thread, and swap it periodically or when I made several changes.

I am not talking about 2D drawing, I am talking about WPF basic controls.

I hope there is something about that. And also the processing of collapsed elements. I think it is faster to have elements collapsed and re-enable instead of remove them and add them when I want to modify the list. But, my previous experience, those collapsed elements still cost quite a lot of calculations. 

A lot of performance issues are with presentation layer instead of raw calculation speed.