8i vs 9i: Difference in "group by" ?

Hi,

is there some known difference in the group by directive between 9i and 8i?

We have an application that runs well on 7.3 to 8i. One customer tried it on a 9i, and it seems a statement like

select Decode(...about 3 lines of code...),foo from tblFoo
group by Decode(...about 3 lines of code...)

is GROUPED by the decode statement, but not ORDERED by it.  From our previous experiences GROUP allways caused an ORDER (unless overwritten with an explizit ORDER BY) - is this "unofficial" behaviour, or is the missing ordering a bug?

(well, we will probably use that chance to clean up that code a bit, using a view instead...)

-- 
                                                   Andreas
if ((sex==fem)&&(hobby==comp)&&(age~25)&&(status==single)
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