Communicate relation between two table
At this time, I'm able to create a relation (1:M) between two table or geometries. After, I user Identify tool to exploit the relation. It is only possible to use this feature when your Identify tool is done on one (1) geometry.
Here my question: Is it possible to select multiple geometries in parent table (select by attribute or location) and communicate to the child table the same selection based on their common attribute (pk,fk).
A partial answer using selection (not relation) has been published for this question. Question on gis.stackexchange.com