On 30 Jul 2015, at 16:47, Mark Rizun <mrizun@gmail.com> wrote:

Pretty much; there is test for equality

RTGroup>>elementFromModel: anObject
    ^ self detect: [ :el | el model = anObject ] ifNone: [ nil ]

and equality is more often than not wanted.

So solution might be to tell Mondrian that you want to compare by identity and not equality?

Exactly! I'd like to have an option to select how I want to compare objects.

It uses already a block to do the comparision��� if you make that pluggable
(add ivar, set it to  [ :el | el model = anObject ] in #initialize, add accessor)
then you can just provide your own block with #== instead.

Marcus