title: WPF DataGrid doesn't shrink when column width shrinks
body: <p>I am using a DataGrid in WPF and want it to shrink to only fit the width of its columns. It does this nicely for the initial rendering. When I resize a column to make it wider the grid grows as well. But if I resize the column to make it narrower again I get white space on the right side of my column (and I can see that the column header grey area is extended beyond the columns.</p>
  
  <p>I would like to have the data grid shrink its width with the columns so I don't get the white space on the right. I have tried to debug the code and as far as I can see the problem is in the DataGridCellsPanel, but I can't see anyplace to fix the width measurement.</p>
  
  <p>Any help would be appreciated.</p>