If you go into the ship designer and use equip mode to add equipment parts, you can then hide those parts one by one with the hide part button.  If you shift select multiple parts, and then use the hide parts button, it will turn the parts semi-transparent to indicate they have been hidden.  However, if you save the design and then call it up, either in a shipyard or in the ship designer, the parts will not actually be hidden. 

I use this hide part feature to hide parts that I don't want to spoil the designed look of the ship.  It is my understanding that the shift select was added for 1.7, and I really appreciate that, but it does not work in Equip mode, which is really where it would be most helpful to ship designers like myself.  Thanks for the feature and the eventual bug fix to follow!