This is somewhat related to another FR:
https://www.photools.com/community/index.php?topic=12517.0
...but is really a different bit of function, so a new FR is warranted.
With a File-Based Event, we control exactly which files are included in the Event. But once created, that File-Based Event does still have a Date Range (per the files it contains). If we later add Files to the Database that should really belong in that Event, IMatch does so automatically, only if the Event is Date-Range-Based.
It would be nice if IMatch offered an option (perhaps available only for File-Based Events), to show all Files that fall within the Event's TimeWindow, that are not in the Event...(and maybe also provide a means to select the ones we would like to add?)
Another option might be for IMatch to alert us to the fact that new files have been added to the database, that potentially "belong in" an existing Date-Based Event (the same way that it alerts us to new Files having been added to the configured Duplicates Category).
As with so many things in IMatch, there is already a means to accomplish what's being requested here...we could go to the TimeLine, select the range of days that the File-Based Event covers, and then Filter for all Files that are not in that Event. But it might be nice for the Events View to provide this facility as an integrated function...
Could this not done via the Events Filter (https://www.photools.com/help/imatch/panel_filter.htm?dl=h-40)?
Yes, the Event Filter could certainly be used to accomplish...(this was maybe a bit frivolous of an FR)...