::mdlListCollector
This command will be used to create a list collector widget and this widget will be attached to the data member specified
in the argument. A list collector is a collector for more than one type and each type has its selection managed independently.
It is like a combobox of collectors of different types and any selection made for each individual type is set independently.
For example, if the mdlListCollector is for a MultiRef member (Point (pt) and Vector (vec)) data member, when the list collector is set to Point, the
selection is set and retrieved from the “pt” data member. When the list collector is set to Vector, the selection is set
and retrieved from the “vec” data member.