Minimum percentage width for the current column.
If your list is 200 pixel wide and you set this
to 25, your column will at least be 50 pixel.
The special value -1 for this parameter means that
the minimum width is as wide as the widest entry in
this column. This ensures that every entry will be
completely visible (as long as the list is wide enough).
Defaults to -1.
Starting with MUI Royale 1.1 this attribute has an applicability
of ISG. In MUI Royale 1.0 the applicability of this attribute was