Sorry for bringing up an old post, but I also have this problem.

The last column of the grid can be made smaller, but I can't make it wider! Because if you want to make it wider, you're dragging further than the grid is wide.

I'm using jqgrid 3.5.3. The problem occurs in IE, Firefox and Chrome (haven't tested in any other browser). I suppose there is a simple solution for this? I have shrinkToFit set to false.