You can open the table if you empty your hand or if your holding other objects, just not a research book.

That is actually an intentional effect of all of my clickable items. I was sick of them not working while having blocks targeted (specifically, the items that need to target blocks), so I made sure that the items take preference to blocks. I might be able to investigate excluding certain items at some point that do not need block-targeting capabilities, but for the initial releases this is how it will be for all clickable items.

Update:

Intentional behavior.

Also, I have decided that I quite like the fact that the items are useable consistently -- i.e. the item activates regardless of what block you are targeting. It always bugged me that the chest i was looking at would activate instead of the item I was trying to use.