Hi, sorry I've confused you. I was trying to explain the difference rather than confuse.
I use the term "In focus" because only one track can have full focus at any one time. Auto track zoom is a great option to use to explain what I mean.....
I'm assuming you have the track view open and several tracks inserted.....
First press Ctrl+Shift+A. Click on track number one anywhere other than the track number.
Now turn on Auto Track Zoom by selecting it from the Track View--->View menu.
Track one will now be zoomed in on vertically and the others collapsed, Track one is the in focus track. Now click on the track header of track two anywhere other than the track number.
The "Focus" of the program has shifted to track two and is "in focus". Any input you make will apply to that track. For example if you have data on the clipboard and press "Ctrl+V" the data will be pasted into track two because it has focus.
Selected is completely different. Select a track by clicking on the tracks number, say track 3. The track number highlights and that track will also now have focus as well. It is selected and in focus.
Now click on track two anywhere other than the track number. The focus has shifted to track two but it is not selected, track three is selected and track two is in focus.
It's important because some actions will apply to the in focus track and selected tracks, some to just the in focus track. Right click and select delete for example. This action will delete two tracks - 2 & 3. Press Ctrl + C to copy and only the data on track 3 will be copied. Press Ctrl + V and the copied data will be pasted into track two.
That particular scenario catches users by surprise at first, in the past there has been loads of complaints on these boards about data being pasted to the "wrong" track, when in reality it's just lack of understanding between "in focus" and "selected". A track can be one or both, selected isn't necessarily in focus and vice versa.
I guess I could have used the term "active" but "in focus" makes more sense to me as it has the input focus of the program and as Scott has pointed out above a selected track can be thought of as "activating" the track for some forms of editing.
I don't think "Highlight" would help for "in focus" either because it isn't "highlighted" as such (although it is a different shade) but a selected track number is actually "highlighted".
That was what I was trying to explain. Sorry for the confusion and hope the above helps.