Not sure if this was happening in past versions, but when in a crafting table you select the dispenser, it populates with the recipe for the dropper instead, omitting the bow in the middle.  Adding the bow manually still allows you to create the dispenser, but built a whole bunch of droppers accidentally before I noticed it was switching on me.

Quick edit.  The switch only happens if you have all the items needed to build the dispenser.  If you select without the proper items (saw without a bow), it properly shows the bow in the recipe being needed, but if you have all the items, it switches over to the dropper upon selection.