… in wpf (not Silverlight) means that the first column is 10x wider than the second. It's like saying “10 parts column 1, and 1 part column 2.” The cool thing about this is that your columns will resize proportionally.
////////////////
//eat up all available space that enclosing container has
////////////////
//Take up as much space as the contents of the column need
///////////////
//Fixed width: 100 pixels
