It is not possible to assign Curative tablet (the right-most item) in the Consumables window.
1920x1080, no scaling, Windows 10, Full-screen (made it windowed in order to take screenshot).
There is no horizontal scrolling. Mouse wheel over any area (checkboxes area/names area/consumable icons area) only results in scrolling (rubber-banding) up-down.
I was only able to assign the tablet by clicking the "Toggle all consumables for Ada", and unchecking all the non-relevant ones.
Steps to Reproduce
1. Have exactly as many consumables as shown on screenshot 2. (maybe relevant) Have only five duplicants 3. Attempt to toggle the rightmost consumable item for only one of the duplicants
This issue has not been confirmed by a developer yet.