Hi, Keni. I haven't really scoped the whole thread but saw the last couple posts and although I haven't fully explored the new lanes yet I was having similar growing pains while dealing with comping different ideas in different takes and doing crops (which were behaving the same way you are describing your split woes). I think the problem is, and it's the same problem I was having, is that you are viewing it from the old school way of cropping/muting/soloing, etc. With the new methods it's all about "promoting", using the various editing modes and finding the correct hotspots on the clips.
So I haven't, as I said, done a full study on this yet otherwise I'd give you step by step directions BUT you are a smart fellow so try the following.
Using the Smart Tool and moving through the different editing modes (right click on the record button in the transport module to access the three modes... you mostly want to try out the new comping mode) then try doing range selects/crops/etc in the top and bottom halves of the clips. The behavior changes.
I'm currently in the middle of getting my new apartment cleaned up and reorganized now that I'm more familiar with the place but I will be doing an in depth study of the "new" ways of editing and will let you know what I find. It seems this has been the evolution of editing and likely what is tripping you up (as well as myself).
It is no longer about cutting things out. It is about making things climb to the top. It's like it's all reversed and flip flopped. It's weird but kind of cool. The hotspots and making sure you are in the right mode though is definitely a little counter intuitive to the way things have been done for... oh the past couple decades but it is pretty quick once you figure it out. It's just very different.
Like with tape you'd cut out what you don't want to be heard and it would hit the floor. Now instead you have a pile of tape on the table and you point at what you want heard and it rises to the top... but you gotta point at it at exactly the right spot.
Sorry that was terribly non technical but as I said I haven't done an in depth study yet. Just a general idea of the concept shift.