Billboard text incorrect position when camera moves in inertia mode.

Hello,

I started billboard demo and i have problem. Text billboards are moving around the screen when I zooming or rotating camera. Problem occurs only when camera is in inertia mode after zooming wheel or releasing right mouse button.

I attached below recorded behaviour posted on YouTube.

I noticed that when you add billboards in xaml file everything is working fine, but i have to inserting text billboards dynamically in program.

Best regards,

Mateusz