You click the date time, a calender opens, if you mouse wheel through the months the same day of the month is highlighted in each month, ie if its the 6 sept, 6 aug and 6 july etc will also be highlighted.
Ok, that's the current behavior, but what's wrong with it?
Well, it seems a little unintuative to me, there is only one today so would have expected 16 nov to be highlighted but not 16th aug, sept, oct, dec jan ... It has caught me out a couple of times when I have seen the highlight and assumed I am viewing the current month. Could be I am just a little slow :)
I guess the current behavior is just fine, take a look at my "research": Windows 7: Scrolling back or forth, selects the first day of the month, scrolling back to current month, both first and current day are selected. Gnome(3.13), Mate(1.6), Unity(7.2), Pantheon(Luna): All have the same behavior, keeps the current day selected across other months. I didn't have time to test this on Windows 8, KDE, Cinnamon, LXDE and others environments I can't remember now.
OK, fair enough :), thanks you for looking into it anyway, I do appreciate it.
Mass-reassign all bugs from florian@ to goodies-dev@, thanks for the maintenance work! (and sorry for the bugmail spam..)
I think the current behavior is fine, Andre's research is correct and this should be closed.