Analysis Workspace - Using shift to select dimension values should only select what user has chosen

Hi

Not sure whether this is working as designed and I've missed a feature, or is a bug/issue...here goes

Scenario:

I have a freeform table with a basic breakdown.  I've dragged over the 'Last Touch Channel' dimension to get a better breakdown of where visitors have come from.  I now want to remove/delete 4 of these channel values and just show one. 

I select 'Email', hold shift and select 'Natural Search' expecting all values between this to be selected, i.e. Email, Session, Direct and Natural.  However what has actually happened is as well as selecting what I want, all metrics/segments/dimensions above have also been selected.  Not what I want, and goes against what I would expect and what my customers expect in terms of the 'hold shift' convention.  I know I can hold Ctrl to unselect these unwanted selections, however wouldn't general convention be to select these only if I explicitly choose them?  Source image file 21796 not available

Thanks

Dan