Control problem when testing device app for Camera Sample?

Question

I am testing the device app for camera on OS Win8RTM. The sample is all right on OS Win8RC. I choose the C++ version .

The initial effect of MFT0 is :

The green part  has part of the screen. The value of slider shows fifty. It's OK!

Now, I change the slider, the value shows one hundred and the effect of Media has show. However the ring of slider is still in the center. It seems there is problem about the slider!!!

Answer 1

Now I close the more option page and then open it again. The ring of slider display the correct position!

The is the same problems about slider of Brightness and Contrast. The ToggleSwitch control is OK!

So I test the C# version and javaScript version of the device app sample. The C# version have the sample problem and  javaScript version is OK!!

I have been tested several times!

Tell me why!

Best wishes!