It appears that it is possible to break the ability to craft, by shift clicking the Dispenser to create the recipe.

This will then cause the inventory to be inaccessible, as clicking on any item will instantly de-select it, so it is impossible to manually craft the dispenser.
The ONLY way to fix this is backing out of the crafting system, and then re-entering.
This is repeatable and will happen again, should you accidently shift click.
It also appears despite having all the ingredients for the dispenser, the recipe is not selected despite having "Craftable" ticked.
A lot of other recipes appear to be "craftable" despite not having the ingredients.