How about a ‘synchronize all’ command that synchronizes every folder in the database? It might take a while, but I’d only have to run it once a week or so – it would save a lot of time. Maybe it could even work on a schedule!
Does Synchronize only sync the current group level, without descending group hierarchies and syncing those?
If so, I’d rather see a generalized “Synchronize Hierarchy” command and use that to synchronize everything from the top-level instead of having a specific “Synchronize All” command to do only that. Or maybe even have a “synchronize descends N level deep” preference.
Either way, the recent post re: bogus post-sync index items would be enough to make me reconsider the idea of syncing large numbers of folders/files in a single pass and having a harder time finding any fallout than when doing smaller batches.
As the upcoming “Synchronize” command checks the selection including all subgroups and their contents, “Synchronize All” is basically identical to selecting all (Cmd-A) and using “Synchronize” afterwards. “Synchronize All” shouldn’t be necessary therefore, IMO.
Ah I see! I guess it simply hadn’t occurred to me to try to synchronize after selecting everything.
And synchronize works by checking modified dates? – So if a file has changed it will replace the older one in the DT database?
DT compares the modification date of contents/files but doesn’t use this date to check if folders referenced by groups contain new files/folders (meaning that DT always checks if there are new files/folders not yet part of the database). Because using the modification date of folders wasn’t reliable over here…
Could some way of excluding subgroups be added? Maybe by holding down the option key modifier when selecting the Synchronize command from the menu? I’d prefer the default be to exclude subgroups, with the option key modifier used to include them, but it’s not that important… I guess it’s easy enough to select all non-group items in a group before the Synchronize. 
There’s a general issue about how certain commands effect subgroups and their contents, like the times I mistakenly set labels or toggled the state of items because of the "inheritance property" of those commands. I have hierarchies with certain groups I’d like excluded from any actions (modifications, classifications, searching). It’s a variation of the "locked group" theme. I’m still thinking through how the UI might support this kind of thing.
One concern is that some unanticipated inheriting-type command will disrupt contents of branches in hierarches, require reverting the database to restore. Being able to lock parts of the database from those potential actions would be one way of handling that.
In the short term, better understanding any "side effect" of commands applied to group vs. non-group items would be useful. For example, it wasn’t clear that Synchronize traversed subgroups.
I enjoy testing different combinations of features and figuring things out on my own but that’s hard when you’re moving faster than I can keep up… but don’t stop.
One option might be to use the flat list of the "History" panel, select the desired items and choose "Synchronize".
Good trick… thanks for that suggestion.