Combo box vs. multiple values (Has other models)

Has issue type	Bug
Has author	dominique.weber
Has responsible person or organization
Has issue description	There seems to be still combo boxes in use for properties that should allow selection of multiple values, which doesn't work (again on the "Decision support techniques" sub form, property "Other models").
Has issue solution
Has issue priority	"high" is not in the list of possible values (1-high, 2-medium, 3-low) for this property.
Has task status