Hmm, it sounds like either the entire update got bugged in the push or your particular download is bugged. I will look into it, but the inventory pop ups should work on the entire slot. The way you are explaining it is how it was broken when I updated UE4 to 4.19. I may have to do a full re-upload of the game to itch.io because the update may have resulted in files from UE4 4.11 and 4.19 being mixed up together and that is no good.
A single left click shouldn't do anything anymore. Only double left click to "use" and a single right click to open the drop down action menu.
How laggy is the mouse cursor? I notice a tiny bit of frame lag, but it "keeps up" with movement on my end if you know what I mean. Does yours actually lag behind where it should be or is it just "choppy" like it isn't drawing every frame?
Thanks again!