1 to see shader effect, we may need render. (not see effect in 3d view about many case,
it depend on how the shader made, I simply think, shader need render to see the effect ^^;)
2 If you use surface selection tool, then select the plane surface in 3d view,
it is same, select surface in surface pane>Editor
(I said both already)
If user think surface selection can not work , you may better send bug report, I believe.
if it can not work with 3d view, surface selection tool has no meaning.
And usually primitive have only one surface group. you can not choose many surface grouop.
Anyway select surface group, in 3d view or surface tab>edit then apply (click ) the shader preset.
and just render as jaderlair suggested already, you can see, your surface change in rendered pic, I believe.
Click thumbnail to see full-size image