Showing Nifty GUI and Game side by side

I am coding a multiplayer 3d chess Game and i have almost completed it but i got stuck when i wanted to show a timer. I have created a timer in nifty that works perfectly. What i want is to show the 3d chess scence in the left of screen and timer with some information of second player in the right portion of screen.
For that purpose i resized the camera of Viewport to 70% of it’s real size in X dimension and puting every element of Nifty Screen in remaining 30% of screen but that is not working. Actually the game is working properly but the Nifty is not updating properly it shows elements of previous screen in the blank portions of current screen.
I think Viewport and GUIViewport are diffrent and both have diffrent camera. So what is wrong?

Well, normally the Nifty viewport is drawn on top of the regular one and so takes advantage of the other viewports clearing the screen. If you don’t have another viewport clearning the frame underneath the nifty viewport then you will have to set its clear flags to clear it.