  We discuss and illustrate the properties of several parton-shower algorithms
available in Pythia and Vincia, in the context of Higgs production via vector
boson fusion (VBF). In particular, the distinctive colour topology of VBF
processes allows to define observables sensitive to the coherent radiation
pattern of additional jets. We study a set of such observables, using the
Vincia sector-antenna shower as our main reference, and contrast it to Pythia's
transverse-momentum-ordered DGLAP shower as well as Pythia's dipole-improved
shower. We then investigate the robustness of these predictions as successive
levels of higher-order perturbative matrix elements are incorporated, including
next-to-leading-order matched and tree-level merged calculations, using Powheg
Box and Sherpa respectively to generate the hard events.
