brundlefly
I meant Source Category = Clips in the export dialog. In your screenshot, it's 'Entire Mix'

OK.  I'll try that.  I have always set this to "entire mix" and it used to work.  But I can certainly try it the other way.  I am trying to export the full mix, of course, as this is the final step in my workflow.  If I select all the clips, and then say category = clips, I should get everything, including all the effects, right?

I think we need to back up and start over - maybe with a new thread. The comments about Clip Tail Duration setting made me think this was about reverb as a Clip FX, but I see now on re-reading that both you and the OP from last July were talking about regular track (or maybe or bus) FX. Clip Tail Duration is only applicable to Clip FX.
 
If this is about reverb in a Track FX bin, there was a thread a while back about an issue with the order and type of FX in the bin causing reverb to cut off at clip ends. I'll hunt it up.
 
EDIT: Here's the thread; Last post says this was fixed in 2016.10:
 
     http://forum.cakewalk.com...us-Fixed-m3472415.aspx

brundlefly
Clip Tail Duration is only applicable to Clip FX.

I think we are getting to the issue now.  I do agree that all the write-ups I have seen on this feature (introduced with Ipswitch in 2015) do refer to "clips".  And in fact, if I select all the MIDI or audio clips I want in the mix, and also select any synth tracks that are driven by that MIDI, then do Export Audio, selecting source = "Clips" (as opposed to "Entire mix", it does work as expected.)  However, that is of no use because that puts each clip out to a separate file.  I want to export the song.
 
I swear it worked correctly for source = "entire mix" until recently.  Maybe I am nuts, but I really would have noticed if things were getting chopped because any chopped reverb becomes audible at the end of the export.
 
So where we are now is I need to confirm I was not imagining this.  Can anybody confirm that the tail duration was indeed added when exporting "entire mix"?

So to confirm the setup and symptoms:
 
- Reverb is part of an FX Chain and has a long/loud enough decay to be heard after approx. 1-second clip fades...?
- Is the FX Chain in Prochannel or track FX bin?
- What reverb plugin?
- What else is in the chain in what order, and what else is before or after the chain?
- Reverb is heard past all clip boundaries on live playback and on freezing the track, but not in export of unfrozen track with Entire Mix...?
- In the export, the reverb is cut off at every clip boundary, not just the last...?
 
If it's just at the end, you might just need to extend your selection in the timline before exporting, or add some automation that runs past the the end of the last clip (volume automation on the Master bus is good for this).

brundlefly
So to confirm the setup and symptoms:
 
- Reverb is part of an FX Chain and has a long/loud enough decay to be heard after approx. 1-second clip fades...?
- Is the FX Chain in Prochannel or track FX bin?
- What reverb plugin?
- What else is in the chain in what order, and what else is before or after the chain?
- Reverb is heard past all clip boundaries on live playback and on freezing the track, but not in export of unfrozen track with Entire Mix...?
- In the export, the reverb is cut off at every clip boundary, not just the last...?
 
If it's just at the end, you might just need to extend your selection in the timline before exporting, or add some automation that runs past the the end of the last clip (volume automation on the Master bus is good for this).

I have two MIDI tracks feeding two channels of a single TTS-1 instance (piano and brass section, just to give it different sounds).  I have no track or effect clips. I put Breverb Hall - Ballroom on the master bus.  That has a tail of about 5 seconds. I have a 5-second tail set in Preferences - File - Audio data and also in Freeze options.
 
1) If I freeze the synth track, the frozen WAV extends 5 seconds beyond the end of the rightmost clip.  But there is no audible tail other than what is inherent in TTS, because Breverb is on the mast bus, not the synth track. This is as expected.
 
With the TTS unfrozen, If I select the 2 MIDI clips, then the ruler start time is the beginning of the leftmost clip and the end time is the end of the rightmost clip. I ctrl-click the TTS track to include it in the export audio.
 
2) When I export audio, selecting "clips" as the source, I get two separate WAV files, one for each clip.  Each one is the duration of that particular clip plus 5 seconds and includes the Breverb tail.  In other words, the times selected on the ruler seem to have no bearing in this case. This is as expected.
 
3) When I export audio, selecting "entire mix" as the source, I get one WAV file that is exactly as long as the ruler time, with NO 5-second tail added. Breverb effect is throughout the file, but chops abruptly after the last note of the rightmost clip.  This is what I am 99% certain has changed for the worse.
 
4) Just for completeness, if I repeat step 3) but select source = "buses" and select the master bus, the file is identical to 3), i.e. no tail added.
 
I realize I could manually stretch the end point on the ruler to achieve the effect of the extra tail length.  I don't believe I have had to do this recently (not since Ipswitch, I guess).  And in the course of editing live concerts, this is not such a simple thing because there is usually applause soon after the last note that I normally want to exclude.  I guess I could but automation on the master fader, but this really should not be necessary.  I think this was working correctly until ???
 
As it is relatively easy to revert releases, I think I will try this next to see if I can find a release where it did work the way I am describing it.

OK, I guess I am insane.  I reverted all the way back to Jamaica Plain and it did not work the way I have described it. 
 
The only thing I can think of is that recently I have been doing a bit more extensive use of reverb buses, along the lines recommended by Mike Senior, so maybe I am pushing the tails out a little longer than before.
 
I appreciate your patience on this.  Clearly it SHOULD offer tails in all cases, not just for clip exports, so I guess I will try to suggest this as an enhancement.

Yes, it's always been necessary to extend the selection to capture FX tails past the last event in a project when exporting with source set to anything other than Clips.
 
As noted above in my previous post, an easy and to have this happen automatically and consistently at the same place every time is to set a Volume envelope on the Master bus that ends  (i.e. the last envelope node) where you want the export to end. Then you'll get the tails without have to select anything when exporting.

brundlefly
As noted above in my previous post, an easy and to have this happen automatically and consistently at the same place every time is to set a Volume envelope on the Master bus that ends  (i.e. the last envelope node) where you want the export to end. Then you'll get the tails without have to select anything when exporting.

Right.  In my case, I usually have a program that runs 60-90 minutes. My workflow is to leave all of this in one project and to split the material at the song boundaries. So if I put this automation on the master bus, I'd have to revers that for the next song each time. I realize that is possible, but it wastes a lot of time, as I am usually trying to get a decent mix on each song and them move on.  For programs like that, I try to mix the entire set of songs in under 2 hours.  I get a good mic on the first song (maybe working 30 minutes on that) then just spot check the remaining songs to make sure nothing major changes.
 
And putting the automation on the master bus still leaves the issue of cutting out the applause.  I could silence the master bus before the applause, but that would also kill the reverb. So I really have to silence all the individual tracks and let the master bus ring.  If the extra tails were handled, that would be exactly what I need.  I'd simply split the songs after the last note, before the applause started, and the extra tail would let the verb ring.
 
With that not being available, the next best (most productive) solution seems to be to put a "fast curve" fade-out that extends all the way to the end of the reverb tail.  With the fast curve, the applause is usually low enough to not be much of an issue.