KG's 11 dimensional retrospection

I just found out that the new WebView component on Windows 8.1 actually DOES NOT support the transparent background color!!!

I did some experiment with DirectX background and using WebView as a UI - it shows only black text - no background color for HTML elements, because of "MinBlend" option...
And I found this thread in MSDN forum:

Background transparency for x-ms-webview element in Windows 8.1?

What is MS thinking?
How could they not support WebView transparent background?
I hoped it is possible, because they announced that with Windows 8.1 they improved the WebView being able to composite with XAML component.
It is actually kind of possible using either "opacity" or CompositeMode="MinBlend", but those are USELESS!
I'm almost shocked with disbelief that they did this.