defect: function with return block in category functions fail to work correctly

What steps will reproduce the problem?
1.select block "function with return" from "category functions"
2.point to "category functions"
3.the category turns blank, i.e., containing no blocks for selection

What is the expected output? What do you see instead?
No "function call" blocks appear in category functions for selection 

What browser are you using?
Google Chrome

Please provide any additional information below.

Original issue reported on code.google.com by shawncs...@gmail.com on 12 Jun 2014 at 2:26

yagamy4680 / blockly

defect: function with return block in category functions fail to work correctly #234