I understand that the new drop-down isn't finished yet.
However, I'm missing now the info what has changed since my last check. Today I noticed that my reputation count had a new value, but I couldn't say by what value it changed, not even if it was higher or lower than on Friday. So I clicked on the new arrow and the column for today and week had all zeroes. So that didn't help. I then clicked on the reputation tab and saw the reason for the change as somebody had upvoted a question of mine on Saturday.
I read a bit here on meta and found a thread that mentioned that a week starts on Sunday and it has to do with timezones and cultural aspects or whatever (mind that a week starts on Monday here). Is that why "week" shows 0?
Long story short, I'm really missing that update info. The envelope was really convenient as it showed what had changed since the last time I had clicked it. To speak for myself I can't yet see how that drop-down is better compared to the envelope, actually I think that you removed quite some functionality.
Would it be possible to extend the new drop-down to hold that update-info please?