I have ALL of my audio and midi tracks selected in an older project, a way older project.
 
I try to line up all of the tracks to a whole measure with the slide process.
 
ALL of the tracks need to go left -00:00:023 
 
I do a CTRL-A to select all tracks from beginning of project to end
 
After all tracks are selected, I do Process/Slide/Ticks/ and set to -23 followed by enter.
 
Does slide process not work for midi in X3?? I am able to slide the audio files, but NOT the midi clips. As far as what I read, it should be any event type.

Guitarmech111
I do a CTRL-A to select all tracks from beginning of project to end

 
You won't be able to slide anything earlier if your selection starts at 1:01:000. You need to set the start of the selection (i.e. From) to the start of the first clip. Lassoing clips with right-click+drag is often the easiest way to do this.

My selection started at 2:01:060 and needed to go back -21 ticks for all tracks.

Should not be a problem, then, but Ctrl+A would have selected from 1:01:000. Check the highlight in the timeline.

brundlefly
Should not be a problem, then, but Ctrl+A would have selected from 1:01:000. Check the highlight in the timeline.

good point. I will verify.

fwiw, I manually selected the midi clip all by itself, from reference point above, and it did not shift when going through the slide process. The audio files did though when trying to slide them together.

Hmmm... all I can tell you is that there isn't any problem with sliding MIDI clips in general that I'm aware of. Either the position is locked or something else project-specific is preventing the slide.

cool, thanks for checking.

here is what happened.
 
When I selected the midi clip all by itself, the selection start was 01:03:000 and I double clicked the clip to bring up the PRV. When I double clicked it, the time selection went from 1:01:000 instead of 1:03:00 where the clip actually started and was selected from.
 
I changed the selection time to 01:03:000 and the midi events shifted the desired amount. My click behavior for double click is supposed to pull up the PRV for midi clips, but does a select all as well. I did not expect that and don't think that the double click should cause the timeline selection to change. It did not do that in 8.5, X1 or X2. But saying that, the clip selection span in the timeline was not persistent once the midi clip was double clicked. 
 
Basically, midi double click and timeline selection is all fubar'd in the X series.

Something still not right. It was a common complaint in X1 that double-clicking to open the PRV would leave all the events selected, but it didn't select anything before the start of the clip. That issue was addressed in X2 or X2a, leaving nothing selected after double-clicking a clip and that behavior persists in X3 for me.
 

I think this may be an issue with older projects(WRK) being imported into X3. I created a new project and inserted a midi track with a few events. When clicking the midi clip, the timeline selected the timeline for the clip. When double clicking that clip, the timeline selection beginning changes to 1:01:000.
 
Gonna shoot Tech support a copy for their use to try a replicate.