To view realtime shader effects, use the Realtime Shaders display modes in any 3D view. These display modes are designed specifically for displaying realtime shaders.
You can use the Realtime Shaders display modes with any viewpoint, including the orthographic views (top, right, front), camera views, and spotlight views. Once you connect a realtime shader tree to the Realtime port of an object's Material node, you'll see your realtime shader effects in any realtime-shaded 3D view.
Set one of the following realtime display modes:
Select Realtime Shaders 
OpenGL from the Display Mode menu of any viewport to display realtime shader effects based on OpenGL (such as GLSL and CgFX shaders).
Select Realtime Shaders DirectX9 from the Display Mode menu of any viewport to display realtime shader effects based on DirectX9 (such as HLSL shaders). To
display effects you must have DirectX 9.0c installed and your graphics hardware must support DirectX 9.0c.
You cannot have a realtime shader active in a viewport display mode other than Realtime Shaders. However, you can put your viewport in Mixed Viewing Mode where selected objects could be displayed in Realtime mode and unselected ones in Wireframe, for example. For more information about setting up for mixed viewing, see the Stereo options in the Camera Display Property Editor [Properties Reference].
