In the German version of the desktop app it says in the backup section under Import and Export: "Alle Einträge als CSV exportieren" which translates to "export all entries as CSV".
"All" to me means really all - but that's not true depending on what you've done before in the app. If you've entered a value into the search field to quickly narrow down the list of entries, then your CSV export contains only the displayed sub-set of of records.
Don't know whether it's a bug or a feature. At least it's a misleading text on the export button.
I'm running mSecure 220.127.116.11 on Windows 10 Pro, 64Bit
Its the same in English - but I've found it a useful feature to be selective in what you are exporting - you can make changes to a batch of records (perhaps changing the type) by exporting the records, deleting the same batch and importing back after changes.
Well - I didn't expect that it differs per language. :-)
I see your point that it can be a useful feature. Now, as I know that "All" is not "All" but "all selected" I can handle it.
Maybe with the next release the developer(s) can add a hint to avoid that somebody falls into the trap.
mSecure 5 for Windows will also export All records for a Group or type if you are in a Group or specific type when exporting your records. I'm not sure if a tip will be added to the app though it would be nice.