I just noticed a great feature: It seems with this release, external project items shared between projects automatically sync. So if a project uses the external class “XYZ,” then changes to XYZ are automatically synced to all open projects! I don’t recall this feature in the past, where I had to close/reopen other projects that shared external items, to get them to update.
Is this new in 2023 R3 or an earlier version of the IDE?
Welcome to the past. 
Xojo has been doing this as long as I can remember. Not sure why it wasn’t happening for you previously!
What OS are you on?
For me, syncing has been working for years. This assumes I have 2 projects open in the same IDE instance (as opposed to launching 2 different IDEs). I’m on macOS only.
macOS; either I’ve never noticed it before, or it wasn’t working when I first used it. But today, I noticed that everything was syncing immediately, which was a nice surprise.
It definitely didn’t use to work. You are not imagining it.
If it now works as expected, that would indeed be nice.
We also had to close and reload projects to get the changes to external items to show up.
I’ll have to test it within our company now. We have lots of projects with external items.
It’s been working for me on macOS for many years. I’m glad it’s working for you now!
It indeed works now.
Very nice.