CF 10 - deserializeJSON

Hi,

in CF 9 I could do

<cfset test = '[{"key1":"value1", "key2":12345, "key3":{"nestedkey1":"nestedvalue1", "nestedkey2":"nestedvalue2"}}]' />

<cfset deserialized = deserializeJSON(test) />

<cfdump var = "#deserialized#" />

and would get a coloured box with the various components of test. With CF 10 all I get is a string with the contents of test. What do I need to do differently in CF 10 to get the coloured box again and - most importantly - to be able to access the parts of the (what I thought it should be) struct resulting from deserializeJSON?

TIA.