Forge and Crafting Invetory, default affix category

When you click on one of the ‘+’ to add an affix shard in the forge, the list of afixes in the crafting inventory is set to the category (prefix/any/suffix) that was last accessed. This seems counter intuitive and offers no percieveable benifit.
I would very much like to suggest that the crafting inventory select the affix category that is relevant for the ‘+’ button that I clicked, why else are there multiple ‘+’'s that I can use to open the crafting inventory.
When I click on an open prefix, I would expect to be shown only prefix shards, and when I click the big ‘+’ in the middle I would expect to be shown all/any affix shards (or at least any that are still relevant to the current craft) and so on for open suffixes.

I often find my self clicking on an open suffix, scrolling down the list of availble affix shards to find something relevant to me, only to realise half way down the list that it is only showing me prefix shards, I don’t get why this is the default behaviour.