If {HEAD ~ the pixel shader debugger link} is selected by {TAIL ~ the user}, then a pixel shader debugger window is opened to display information regarding the pixel shader used for the selected pixel 
is selected by
If { HEAD ~ the pixel shader debugger link } is selected by { TAIL ~ the user } , then a pixel shader debugger window is opened to display information regarding the pixel shader used for the selected pixel
OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH