I did the honors.
[CWBRN-43285]

I tried this as request in large mode, which is how I normally have it, Auto and collapsed without issue.  Having said that I had to have the smart tool turned on if I used the arrow or select tool then I could not make changes in the event inspector.

Is that a possibility that you had by accident used the select tool to do a selection and then not reverted to the smart tool?

Excellent! I think you have already hit an inconsistency.
 
My EI is set to Large, too.
 
I have just created a fresh blank project, added one single midi track, opened the PRV view (Alt+3), added one single note with the smart tool, changed to select tool, and...
 
I can edit the note's values with the Select tool.
 
I switch back to Smart tool, and...
I can edit the note's values with the Smart tool, too.
 
But remember, John was able to edit in Large mode, but NOT in Hover-Popup (Flyout) mode.
Yet when I tried it, both modes worked. As do the other editable tools on the bar. Only E.I. is so far behaving inconsistently in this respect.

I don't know how reproducible this is. Out of curiosity I tried with an old project, a new project, EI collapsed, EI large, single notes, multiple notes, track view inline PRV, and regular PRV. I could use any tool to change values...in all cases it worked as expected.  

Same project, messing around. Now I have the same that you had.
 
"Select" tool is active:
If I click on a note (I have 2 notes now) then the value is displayed in the E.I.
If I click in the E.I. with the Select tool active, I cannot edit.
 
BUT:
If I LASSO a single note with the "Select" tool, THEN I can go to the E.I. and edit the value!
 
A closer look has revealed that the Select tool is somehow selecting the note for the E.I. but not activating the note. In other words, it stays light blue (in my case now), and if I lasso it, it goes dark blue.

Craig, sorry, our postings crossed each other.
Perhaps try a fresh Blank project with just one Midi track and just one or two notes.

After a closer look I see the values being displayed in the E.I. are those of the first note, not those of the note I highlighted with the lasso.
 
If I lasso the second note, click on "Time" in the E.I. and hit enter, the second note jumps to the start position of the first note.
 
In other words, the values shown are not those of the highlighted note. But if you edit a value, the resulti is given to the highlighted note (even if you just hit Enter).

I have returned the E.I. to Collapsed(Flyout) mode and am getting more crazy inconsistencies.
I wanted to find reproducible steps but I am not making progress.
 
I hear the dinner bell ringing. Time to pack it in.

jpetersen
If I click in the E.I. with the Select tool active, I cannot edit.
 
BUT:
If I LASSO a single note with the "Select" tool, THEN I can go to the E.I. and edit the value!
 
A closer look has revealed that the Select tool is somehow selecting the note for the E.I. but not activating the note. In other words, it stays light blue (in my case now), and if I lasso it, it goes dark blue.

This is the only problem that I can replicate - the failure of the Select Tool to select notes in the PRV on left-click. I believe this came up a while back, well before Lexington.
 
So long as notes are successfully selected, the Event inspector is working consistently for me.

jpetersen
After a closer look I see the values being displayed in the E.I. are those of the first note, not those of the note I highlighted with the lasso.
 
If I lasso the second note, click on "Time" in the E.I. and hit enter, the second note jumps to the start position of the first note.
 
In other words, the values shown are not those of the highlighted note. But if you edit a value, the resulti is given to the highlighted note (even if you just hit Enter).

Could this perhaps be due to the revamping of the PRV at the start of the year? I know certain aspects and I think procedures have been altered. Maybe the selection process/how the tools work has changed.
 
Just a thought based on Brindlefly's observations.