I've found that once I've highlighted the programs I want to transfer, it's really picky about what row you are on before you can move over into the actions box. For example, if you are in the last row, it won't move over into the actions tiles. But if you just move up and then right it will go into the actions area. Did you try that? It's always been that way.
And yes, I have a 6TB and a 2TB both connected for 8TB. You can look up my postings and pictures of the setup in the other thread. Again, I think I just lucked out with the right combination of enclosures and hub but I posted the direct Amazon links to the enclosure and hub that I use.