In the case of idiomatic particle verb constructions, a mechanism specific to XLFG was used. This allowed us to propose a preferential choice of the idiomatic expression by adding a special entry in the lexicon.
This way of prioritizing an idiomatic construction, if it exists, and fall back on a compositional construction by default, seems to be coherent with both the FLG formalism and an approach where the lexicon takes a prominent place in the analysis of such phenomena.