How do I connect the carts with a chain? Tried clicking one then the other, tried placing between the two (this resulted in the chain just being placed vertically like a normal chain), etc. Cannot get them to connect. I checked the config menu and it is enabled, so. What's wrong/how do I do it?

Shift right click the leading cart with the chain, then the following cart

Uhh.. so... my minecart with furnace appears to have taken my chain from me and used it as a fuel when I did this

Starting with shift right clicking the regular mine cart and then the minecart with furnace made it work, but perhaps that's a bug that should be fixed? I'll add it as its own issue report for you since technically the posted issue is fixed. Thanks for the prompt help tho!

Wont work, can tell you now. The bug you mentioned has already been fixed in Dev, just hasnt been pushed

Yea

Is this also the case with the minecart with chest? Usually does nothing but sometimes the chest cart will delete my chain.