cubicweb-relationwidget #10184514 Allow more uicfg customizations [validation pending]

This includes:

  • setting the initial value
  • hiding the creation form
  • pop-up javascript arguments
prioritynormal
typeenhancement
done in0.3.3
load0.500
load left0.000
closed by<not specified>
patch[view] Use initial value from uicfg if any [applied]