[Interest] ListModels with sections, not grouping by section

[Jason H]

So I'm trying to use sections, and it seems that the data must be explicit  ordered by section otherwise you get the section repeated whenever it changes that is to say:
[
  { 'a':'A' 'b':'1'}
  { 'a':'B' 'b':'2'}
  { 'a':'C' 'b':'1'}
]
section by 'b', we get three groups:
1
+ A
2 
+ B
1 
+ C

Whereas I expected:
1
+ A
+ C
2
+ B

Is there some property I need to set or something?

Thanks