BTW 1.3.12 has this issue so it's nothing to do with Michael's fix for bug 310.

(In reply to comment #0)
Confirmed on Mac with 1.3.13-alpha March 17 2010. Changed Platform to OS X and Linux.

I see the same behavior on Windows as is described for the others.

The second track becomes selected only if there is any mouse motion before button up.  You might have to click and release carefully to see it.

What is the correct general description of how you think click should behave?  Considering that there may be any number of tracks, and any subset of those might be in selected state, and any one of the tracks may be shift-clicked?  It is not obvious.

What happens typically in list boxes, where you can ctrl-click to make arbitrary subsets, and then shift-click after that?  It is an analogous problem and I don't know if there is anything like a convention here.  I just tried in in one program on windows, and it appears that the most recently picked row is taken as the other end of the range to highlight, disregarding the state of all other rows.

But the existing behavior of Audacity is simple enough and understandable.

Fix made, but see bug 1425

https://github.com/audacity/audacity/commit/dd786984db63d2ed4425322aed3e67437fff2202

Works for me on W10 audacity-win-r53e30e5-2.1.3-alpha-27-jun-16

Testing on c9422aa 08Jul16 on Mac El Capitan

At Step 3:
a) if I click near the start in the other track then noth tracks show the selection
b) if I click near the start in the original track then the other track just shows the sunc-lock clocks

On W10 in whichever tarck you make the sevcod click, the second click only shows the sync-lock clocks.

I'm uncertain as to what expected behaviors should be

I've had a careful read of the (released) manual and it only seems to mention using click then Shift+click on a single track not multiple tracks - so this does not clarify expected behavior for me (or any user come to that)

I also note the on W10 2.1.2 I ger the same behavior ase desribed in Comment #7

(In reply to Peter Sampson from comment #7)
I think the behaviour is the same on all platforms. Step 3 is a SHIFT-click.

As per my comment in http://bugzilla.audacityteam.org/show_bug.cgi?id=1425#c5, if we keep these changes I think we must enable CTRL-click in the waveform so that you can still select in track 1 then mouse select in track 3 without selecting track 2. 

And yes the change in behaviour of SHIFT-click and addition of CTRL-click (currently only working for Track Control Panel and Mixer Board clicks) will need to be documented in the Manual.

In the new behaviour for selections I noticed this with two tracks.

Drag a selection in lower track then drag into upper track. SHIFT-click in upper track keeps both tracks selected. SHIFT-click in lower track deselects the upper track.

But, drag a selection in lower track then UP arrow and ENTER. Now, SHIFT-click in the upper track deselects the the lower track. So it seems to be remembering where the drag ended? But these are complex cases and the behaviour above seems reasonable to me.

Note that ctrl+click in the waveform was like quick play before 2.1.1, and in 2.1.1, 2.1.2 it starts scrubbing.  Now it does nothing.  Are we sure we need to repurpose it once more?  Or should we leave it available for something else in the future?

Regarding shift-click, the rule is that where you last made button-down without shift, or where you last hit ENTER, there is the other endpoint for determining the range selected by shift-click.  The button-down rule is consistent with the behavior I see on Mac selecting in listboxes, like those on this Bugzilla page.

(In reply to Paul L from comment #11)
> Note that ctrl+click in the waveform was like quick play before 2.1.1, 
> and in 2.1.1, 2.1.2 it starts scrubbing.  Now it does nothing.  Are we 
> sure we need to repurpose it once more?  Or should we leave it available
> for something else in the future?
If you want your changes, I see no choice but to repurpose CTRL + click. Otherwise AFAICT you can no longer in one mouse operation select in track 1 then change the selection and add it to track 3 without doing so also in track 2, which is a very common operation. 

Also without that repurpose, modified clicks in Track Control Panel/Mixer Board  would be inconsistent with such clicks in waveform. 

There may well be better uses of CTRL-click in the waveform, perhaps when we have discontinuous multiple selections, to add the entirety of another clip to the selection. But we need some one step way to do what I mention in the first paragraph above.

Accepting this fix. Request to repurpose CTRL-click in waveform to toggle the selection is at bug 1484.