3 simple questions about Mail in 10.11.2

I'm still learning with my new iMac which shipped with 10.11.1 updated to 10.11.2.

1. When new mail arrives in the Inbox, it always used to have a small blue dot to the left indicating that it was unread. Silly me can't find a way of getting this.

2. Just under the toolbar, I have my frequently used mailboxes. To remove one of these, I would click-drag it out of the bar and whoosh - gone. Well it makes the whooshing noise, but doesn't budge. Doing something wrong?

3. At the bottom of the mailbox list on the left, there used to be a "+" next to a "triangle" next to a "Gear wheel". None in my case. Clicking on the "triangle" opened up the activity monitor. Are they gone now or am I missing some command to get them?

Thank you for taking the trouble over, what are, relatively trivial things.

Ian

I'm embarrassed to say that I have learnt a bit more since I posted above. The Blue Dot problem is apparently well known. With some, it won't go away; that is, even when the message is read, the dot persists. With a minority, the dot never, or only intermittently, appears. Hopefully sorted with the next update.

The activity monitor, as was, is gone, but by clicking Window > Activity, you can get a floating activity window.

However, the Favourite Mailbox Bar problem persists. I can click & drag the mailbox out of the bar, it does its exploding act accompanied by the whoosh; but remains firmly in the Favourites Bar. That goes for any/all of them. That's a problem I would appreciate some help with.

Ian