Tags used to auto complete in Mv4 and now they don't. There is a drop down list to pick from, but they are in completely random order. It helps slightly, but would be much more helpful if the list was at least alphabetical. I know the auto complete is possible because the envelope field has it. I start typing and it pops up a couple to pick from based on what I typed.
Is this feature going to be added? It is taking up sooo much time to manually type the whole thing each time.