NDi audio is fine, there's plenty uses around, just avoid the integrated ndi in arena and use another solution to serve it. In fact, you can use the official ndi tools to send the arena composition with audio out of the box.
Combobox is even more complicated to me, and SLOW (is almost the same that pick up a deck from compositions panel, aside the modification-save thing). I don't want to type or check a list to pick one tab (usually named 01..36, misc13,various24..). I just want a click and see the next 30 tabs, or the...
A simplest one: load your BG clip (columns and so), apply a crop and make a preset.
Then use that preset with your text clips to fit the content on that crop.
Turn it off when it's ok.
I think DXV has no chance to screw up things on that side, is just AE.
Check if you're rendering with Premultiplied (matted) instead of straight alpha.
I bet you're premultiplying by lime, tasty but wrong for alpha creation.
I personally don't think a scrollbar is the solution for this. I think the layer scroll buttons should be more responsive, and when you hold them the should scroll the deck list speeding up, so you don't need to click much. Holding a button can reduce clicks, but is a way to SLOW things down. Multi...
