problem with transparency in Matlab
 

Hello,
I am trying to make one patch transparent.
What the documentation says about making only the specified object transparent is this:
"alpha(object_handle,value) sets the transparency property only on the object identified by object_handle."

However what I get is all pathces being transparent, even though I use ALPHA with a handle to the particular patch.

My code for the transparency is like this:

pol = patch(polx,poly,[1,1,0.5]); 

alpha(pol,0.5); 

set(gcf,'Renderer','OpenGL');

Have anybody encountered such a problem before and could help please?