anchor.diff:  === Multiple Selection
   
   In the multiple selection mode, a user can select multiple items by clicking on
  -the checkboxes in the leftmost column, or by using the spacebar to select/deselect the currently focused row.
  -(space key is a customizable default).
  +the checkboxes in the leftmost column.
   
   [[figure.components.grid.selection.multi]]
   .Multiple Selection in  [classname]#Grid#
  
positive.code: * Grid has no generated columns. Instead, the container data source can be wrapped around a [classname]#GeneratedPropertyContainer#.
  * No column icons; you can implement them in a column with an [classname]#ImageRenderer#.
  * Components can not be shown in Grid cells; instead the much more efficient renderers can be used for the most common cases, and row editor for editing values.
  * Limited support for drag and drop: the user can drag columns to reorder them.
  
  In addition, Grid has the following visual changes:
  
  
negative.code: You can specify minimum and maximum widths for the expanding columns with
  [methodname]#setMinimumWidth()# and [methodname]#setMaximumWidth()#,
  respectively.
  
  
  [[components.grid.columns.frozen]]
  